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ECON 216 STATISTICS FOR MANAGERS NAME: __________________STUDENT ID: _______ Ben Kahn FINAL EXAM PART I MCLA FINAL EXAM PART I-50 points 1) Please provide a complete response to each question in order to receive full credit. Chapter 2 Organizing and Visualizing Data TABLE 2-1 An insurance company evaluates many numerical variables about a person before deciding on an appropriate rate for automobile insurance. A representative from a local insurance agency selected a random sample of insured drivers and recorded, X, the number of claims each made in the last 3 years, with the following results. X f 1 14 2 18 3 12 4 5 5 1 2) Referring to Table 2-1, how many drivers are represented in the sample? 3) Referring to Table 2-1, how many total claims are represented in the sample? TABLE 2-3 Every spring semester, the School of Business coordinates a luncheon with local business leaders for graduating seniors, their families, and friends. Corporate sponsorship pays for the lunches of each of the seniors, but students have to purchase tickets to cover the cost of lunches served to guests they bring with them. The following histogram represents the attendance at the senior luncheon, where X is the number of guests each graduating senior invited to the luncheon and f is the number of graduating seniors in each category. 4) Referring to the histogram from Table 2-3, how many graduating seniors attended the luncheon? 5) A professor of economics at a small Texas university wanted to determine what year in school students were taking his tough economics course. Shown below is a pie chart of the results. What percentage of the class took the course prior to reaching their senior year? Chapter 3 Numerical Descriptive Measures 6) According to the Chebyshev rule, at least 93.75% of all observations in any data set are contained within a distance of how many standard deviations around the mean? 7) According to the Chebyshev rule, at least what percentage of the observations in any data set are contained within a distance of 3 standard deviations around the mean? 8) According to the Chebyshev rule, at least what percentage of the observations in any data set are contained within a distance of 2 standard deviations around the mean? TABLE 3-1 Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for Medicaid. The ages of 25 senior citizens were as follows: 60 61 62 63 64 65 66 68 68 69 70 73 73 74 75 76 76 81 81 82 86 87 89 90 92 9) Referring to Table 3-1, calculate the arithmetic mean age of the senior citizens to the nearest hundredth of a year. Answer: Difficulty: Easy Keywords: arithmetic mean 10) Referring to Table 3-1, determine the median age of the senior citizens. Answer: Difficulty: Easy Keywords: median 11) Referring to Table 3-1, determine the first quartile of the ages of the senior citizens. Answer: Difficulty: Moderate Keywords: quartiles 12) Referring to Table 3-1, determine the third quartile of the ages of the senior citizens. Answer: Difficulty: Moderate Keywords: quartiles 13) Referring to Table 3-1, determine the interquartile range of the ages of the senior citizens. Answer: Difficulty: Moderate Keywords: interquartile range 14) Referring to Table 3-1, determine which of the following is the correct statement. A) One fourth of the senior citizens sampled are below 65.5 years of age. B) The middle 50% of the senior citizens sampled are between 65.5 and 73.0 years of age. C) The mean age of senior citizens sampled is 73.5 years of age. D) All of the above are correct. Answer: Difficulty: Moderate Keywords: quartiles, arithmetic mean 15) Referring to Table 3-1, identify which of the following is the correct statement. A) One fourth of the senior citizens sampled are below 64 years of age. B) The middle 50% of the senior citizens sampled are between 65.5 and 73.0 years of age. C) 25% of the senior citizens sampled are older than 81.5 years of age. D) All of the above are correct. Answer: Difficulty: Moderate Keywords: quartiles Chapter 6 The Normal Distribution and Other Continuous Distributions 16) In its standardized form, the normal distribution A) has a mean of 0 and a standard deviation of 1. B) has a mean of 1 and a variance of 0. C) has an area equal to 0.5. D) cannot be used to approximate discrete probability distributions. Answer: Keywords: standardized normal distribution, properties 17) Given that X is a normally distributed variable with a mean of 50 and a standard deviation of 2, find the probability that X is between 47 and 54. Answer: Keywords: standardized normal distribution, probability 18) A company that sells annuities must base the annual payout on the probability distribution of the length of life of the participants in the plan. Suppose the probability distribution of the lifetimes of the participants is approximately a normal distribution with a mean of 68 years and a standard deviation of 3.5 years. What proportion of the plan recipients would receive payments beyond age 75? Answer: Difficulty: Easy Keywords: standardized normal distribution, probability 19) A company that sells annuities must base the annual payout on the probability distribution of the length of life of the participants in the plan. Suppose the probability distribution of the lifetimes of the participants is approximately a normal distribution with a mean of 68 years and a standard deviation of 3.5 years. What proportion of the plan recipients die before they reach the standard retirement age of 65? Answer: Difficulty: Moderate Keywords: standardized normal distribution, probability 20) A company that sells annuities must base the annual payout on the probability distribution of the length of life of the participants in the plan. Suppose the probability distribution of the lifetimes of the participants is approximately a normal distribution with a mean of 68 years and a standard deviation of 3.5 years. Find the age at which payments have ceased for approximately 86% of the plan participants. Answer: Difficulty: Difficult Keywords: standardized normal distribution, value 21) A catalog company that receives the majority of its orders by telephone conducted a study to determine how long customers were willing to wait on hold before ordering a product. The length of waiting time was found to be a variable best approximated by an exponential distribution with a mean length of waiting time equal to 3 minutes (i.e. the mean number of calls answered in a minute is ). What proportion of customers having to hold more than 4.5 minutes will hang up before placing an order? 22) If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the probability that a randomly selected college student will take between 2 and 4.5 minutes to find a parking spot in the library parking lot. 23) The owner of a fish market determined that the average weight for a catfish is 3.2 pounds with a standard deviation of 0.8 pound. Assuming the weights of catfish are normally distributed, the probability that a randomly selected catfish will weigh more than 4.4 pounds is ________. Answer: 24) The amount of tea leaves in a can from a particular production line is normally distributed with μ = 110 grams and σ = 25 grams. What is the probability that a randomly selected can will contain between 100 and 120 grams of tea leaves? Answer: 25) The amount of tea leaves in a can from a particular production line is normally distributed with μ = 110 grams and σ = 25 grams. What is the probability that a randomly selected can will contain less than 100 grams of tea leaves? Answer: 26) You were told that the amount of time lapsed between consecutive trades on the New York Stock Exchange followed a normal distribution with a mean of 15 seconds. You were also told that the probability that the time lapsed between two consecutive trades to fall between 16 to 17 seconds was 13%. The probability that the time lapsed between two consecutive trades would fall below 13 seconds was 7%. What is the probability that the time lapsed between two consecutive trades will be longer than 17 seconds? Answer: Sampling from Finite Populations 27) The use of the finite population correction factor when sampling without replacement from finite populations will A) increase the standard error of the mean. B) not affect the standard error of the mean. C) reduce the standard error of the mean. D) only affect the proportion, not the mean. Answer: Difficulty: Easy Keywords: finite population correction 28) You use the finite population correction factor when A) you sample without replacement and the sample size is larger than 5% of the population size. B) you sample without replacement and the sample size is smaller than 5% of the population size. C) you sample with replacement and the sample size is larger than 5% of the population size. D) you sample with replacement and the sample size is smaller than 5% of the population size. Answer: 29) The finite population correction factor is A) . B) . C) . D) . Answer: TABLE 7-7 Times spent studying by students in the week before final exams follow a normal distribution with standard deviation 8 hours. A random sample of 4 students was taken from a population of 50 in order to estimate the mean study time for the population of all students. Use the finite population correction. 30) Referring to Table 7-7, what is the standard error of all the sample means? Answer: Difficulty: Moderate Keywords: sampling distribution, mean, probability, finite population correction 31) Referring to Table 7-7, what is the probability that the sample mean differs from the population mean by less than 2 hours? Answer: Difficulty: Moderate Keywords: sampling distribution, mean, probability, finite population correction Chapter 9 Fundamentals of Hypothesis Testing: One-Sample Tests 32) Which of the following would be an appropriate null hypothesis? A) The mean of a population is equal to 55. B) The mean of a sample is equal to 55. C) The mean of a population is greater than 55. D) Only A and C are appropriate. Answer: Difficulty: Easy Keywords: form of hypothesis 33) Which of the following would be an appropriate alternative hypothesis? A) The population proportion is less than 0.65. B) The sample proportion is less than 0.65. C) The population proportion is not less than 0.65. D) The sample proportion is not less than 0.65. Answer: Difficulty: Easy Keywords: form of hypothesis 34) A Type II error is committed when A) you reject a null hypothesis that is true. B) you don't reject a null hypothesis that is true. C) you reject a null hypothesis that is false. D) you don't reject a null hypothesis that is false. Answer: Difficulty: Easy Keywords: Type II error 35) A Type I error is committed when A) you reject a null hypothesis that is true. B) you don't reject a null hypothesis that is true. C) you reject a null hypothesis that is false. D) you don't reject a null hypothesis that is false. Answer: Difficulty: Easy Keywords: Type I error 36) If an economist wishes to determine whether there is evidence that mean family income in a community exceeds $50,000, A) either a one-tail or two-tail test could be used with equivalent results. B) a one-tail test should be utilized. C) a two-tail test should be utilized. D) None of the above. Answer: Difficulty: Easy Keywords: one-tail test 37) How many tissues should the Kimberly Clark Corporation package of Kleenex contain? Researchers determined that 60 tissues is the mean number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: = 52, S = 22. Give the null and alternative hypotheses to determine if the number of tissues used during a cold is less than 60. A) H0 : μ ≤ 60 and H1 : μ > 60. B) H0 : μ ≥ 60 and H1 : μ < 60. C) H0 : ≥ 60 and H1 : ≠ 52. D) H0 : = 52 and H1 : ≠ 52. Answer: Difficulty: Moderate Keywords: one-tail test, form of hypothesis, mean, t test 38) How many tissues should the Kimberly Clark Corporation package of Kleenex contain? Researchers determined that 60 tissues is the mean number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: = 52, S = 22. Using the sample information provided, calculate the value of the test statistic. A) t = (52 - 60) / 22 B) t = (52 - 60) / (22 / 100) C) t = (52 - 60) / (22 / 1002) D) t = (52 - 60) / (22 / 10) Answer: Difficulty: Easy Keywords: one-tail test, mean, t test 39) How many tissues should the Kimberly Clark Corporation package of Kleenex contain? Researchers determined that 60 tissues is the mean number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: = 52, S = 22. Suppose the alternative you wanted to test was H1 : μ < 60. State the correct rejection region for α = 0.05. A) Reject H0 if t > 1.6604. B) Reject H0 if t < -1.6604. C) Reject H0 if t > 1.9842 or Z < -1.9842. D) Reject H0 if t < -1.9842. Answer: Difficulty: Moderate Keywords: one-tail test, mean, t test, rejection region 40) How many tissues should the Kimberly Clark Corporation package of Kleenex contain? Researchers determined that 60 tissues is the mean number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: = 52, S = 22. Suppose the test statistic does fall in the rejection region at α = 0.05. Which of the following decisions is correct? A) At α = 0.05, you do not reject H0. B) At α = 0.05, you reject H0. C) At α = 0.10, you do not reject H0. D) At α = 0.10, you reject H0. Answer: Difficulty: Easy Keywords: one-tail test, mean, t test, decision 41) How many tissues should the Kimberly Clark Corporation package of Kleenex contain? Researchers determined that 60 tissues is the mean number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: = 52, S = 22. Suppose the test statistic does fall in the rejection region at α = 0.05. Which of the following conclusions is correct? A) At α = 0.05, there is not sufficient evidence to conclude that the mean number of tissues used during a cold is 60 tissues. B) At α = 0.05, there is sufficient evidence to conclude that the mean number of tissues used during a cold is 60 tissues. C) At α = 0.05, there is insufficient evidence to conclude that the mean number of tissues used during a cold is not 60 tissues. D) At α = 0.10, there is sufficient evidence to conclude that the mean number of tissues used during a cold is not 60 tissues. Answer: Difficulty: Moderate Keywords: two-tail test, mean, t test, conclusion PROBABILITY Chapter 4 Basic Probability 67) A survey of banks revealed the following distribution for the interest rate being charged on a home loan (based on a 30-year mortgage with a 10% down payment). 3.20% 3.30% 3.40% 3.50% 3.60% to to to to and Interest Rate 3.29% 3.39% 3.49% 3.59% above Probability 0.12 0.23 0.24 0.35 0.06 If a bank is selected at random from this distribution, what is the chance that the interest rate charged on a home loan will exceed 3.49%? A) 0.06 B) 0.41 C) 0.59 D) 1.00 Answer: Difficulty: Easy Keywords: marginal probability, addition rule TABLE 4-1 Mothers Against Drunk Driving is a very visible group whose main focus is to educate the public about the harm caused by drunk drivers. A study was recently done that emphasized the problem we all face with drinking and driving. Four hundred accidents that occurred on a Saturday night were analyzed. Two items noted were the number of vehicles involved and whether alcohol played a role in the accident. The numbers are shown below: 68) Referring to Table 4-1, what proportion of accidents involved more than one vehicle? A) 50/400 or 12.5% B) 75/400 or 18.75% C) 275/400 or 68.75% D) 325/400 or 81.25% Answer: Difficulty: Easy Keywords: contingency table, empirical classical probability, addition rule 70) Referring to Table 4-1, what proportion of accidents involved alcohol or a single vehicle? A) 25/400 or 6.25% B) 50/400 or 12.5% C) 195/400 or 48.75% D) 245/400 or 61.25% Answer: Difficulty: Easy Keywords: contingency table, empirical classical probability, addition rule 72) Referring to Table 4-1, given that multiple vehicles were involved, what proportion of accidents involved alcohol? A) 120/170 or 70.59% B) 120/230 or 52.17% C) 120/325 or 36.92% D) 120/400 or 30% Answer: Difficulty: Easy Keywords: contingency table, empirical classical probability, conditional probability, addition rule Probability Counting Rules 73) A new model car from Ford Motor Company offers a keyless entry system that utilizes a four-letter code. How many different possible combinations are there for the code? Answer: Difficulty: Easy Keywords: counting rule Chapter 5 Discrete Probability Distributions 76) If n = 10 and π = 0.70, then the mean of the binomial distribution is A) 0.07. B) 1.45. C) 7.00. D) 14.29. Answer: Difficulty: Easy Keywords: binomial distribution, mean 77) If n = 10 and π = 0.70, then the standard deviation of the binomial distribution is A) 0.07. B) 1.45. C) 7.00. D) 14.29. Answer: Difficulty: Easy Keywords: binomial distribution, standard deviation TABLE 5-4 The following table contains the probability distribution for X = the number of traffic accidents reported in a day in Corvallis, Oregon. X 0 1 2 3 4 5 P(X) 0.10 0.20 0.45 0.15 0.05 0.05 78) Referring to Table 5-4, the mean or expected value of the number of accidents is ________. Answer: Difficulty: Easy Keywords: probability distribution, mean REGRESSION ANALYSIS Chapter 13 Simple Linear Regression 1) The Y-intercept (b0) represents the A) predicted value of Y when X = 0. B) change in estimated Y per unit change in X. C) predicted value of Y. D) variation around the sample regression line. Answer: Difficulty: Easy Keywords: intercept, interpretation 2) The Y-intercept (b0) represents the A) estimated average Y when X = 0. B) change in estimated average Y per unit change in X. C) predicted value of Y. D) variation around the sample regression line. Answer: Difficulty: Easy Keywords: intercept, interpretation 3) The slope (b1) represents A) predicted value of Y when X = 0. B) the estimated average change in Y per unit change in X. C) the predicted value of Y. D) variation around the line of regression. Answer: Difficulty: Easy Keywords: slope, interpretation 4) The least squares method minimizes which of the following? A) SSR B) SSE C) SST D) All of the above. Answer: Difficulty: Difficult Keywords: least squares, properties TABLE 13-1 A large national bank charges local companies for using their services. A bank official reported the results of a regression analysis designed to predict the bank's charges (Y)— measured in dollars per month—for services rendered to local companies. One independent variable used to predict service charges to a company is the company's sales revenue (X)— measured in millions of dollars. Data for 21 companies who use the bank's services were used to fit the model: Yi = β0 + β1Xi + εi The results of the simple linear regression are provided below. 5) Referring to Table 13-1, interpret the estimate of β0, the Y-intercept of the line. A) All companies will be charged at least $2,700 by the bank. B) There is no practical interpretation since a sales revenue of $0 is a nonsensical value. C) About 95% of the observed service charges fall within $2,700 of the least squares line. D) For every $1 million increase in sales revenue, we expect a service charge to decrease $2,700. Answer: Difficulty: Moderate Keywords: intercept, interpretation 6) Referring to Table 13-1, interpret the estimate of σ, the standard deviation of the random error term (standard error of the estimate) in the model. A) About 95% of the observed service charges fall within $65 of the least squares line. B) About 95% of the observed service charges equal their corresponding predicted values. C) About 95% of the observed service charges fall within $130 of the least squares line. D) For every $1 million increase in sales revenue, we expect a service charge to increase $65. Answer: Difficulty: Difficult Keywords: standard error of estimate, interpretation 7) Referring to Table 13-1, interpret the p-value for testing whether β1exceeds 0. A) There is sufficient evidence (at the α = 0.05) to conclude that sales revenue (X) is a useful linear predictor of service charge (Y). B) There is insufficient evidence (at the α = 0.10) to conclude that sales revenue (X) is a useful linear predictor of service charge (Y). C) Sales revenue (X) is a poor predictor of service charge (Y). D) For every $1 million increase in sales revenue, you expect a service charge to increase $0.034. Answer: Difficulty: Moderate Keywords: p-value, interpretation 8) Referring to Table 13-1, a 95% confidence interval for β1 is (15, 30). Interpret the interval. A) You are 95% confident that the mean service charge will fall between $15 and $30 per month. B) You are 95% confident that the sales revenue (X) will increase between $15 and $30 million for every $1 increase in service charge (Y). C) You are 95% confident that mean service charge (Y) will increase between $15 and $30 for every $1 million increase in sales revenue (X). D) At the α = 0.05 level, there is no evidence of a linear relationship between service charge (Y) and sales revenue (X). Answer: Difficulty: Moderate Keywords: confidence interval, interpretation TABLE 13-2 A candy bar manufacturer is interested in trying to estimate how sales are influenced by the price of their product. To do this, the company randomly chooses 6 small cities and offers the candy bar at different prices. Using candy bar sales as the dependent variable, the company will conduct a simple linear regression on the data below: City Price ($) Sales River City 1.30 100 Hudson 1.60 90 Ellsworth 1.80 90 Prescott 2.00 40 Rock Elm 2.40 38 Stillwater 2.90 32 9) Referring to Table 13-2, what is the estimated slope for the candy bar price and sales data? A) 161.386 B) 0.784 C) -3.810 D) -48.193 Answer: Difficulty: Moderate Keywords: slope, estimation 12) Referring to Table 13-2, what is the percentage of the total variation in candy bar sales explained by the regression model? A) 100% B) 88.54% C) 78.39% D) 48.19% Answer: Difficulty: Moderate Keywords: coefficient of determination, interpretation 13) Referring to Table 13-2, what percentage of the total variation in candy bar sales is explained by prices? A) 100% B) 88.54% C) 78.39% D) 48.19% Answer: Difficulty: Moderate Keywords: coefficient of determination, interpretation 17) Referring to Table 13-2, to test that the regression coefficient, β1, is not equal to 0, what would be the critical values? Use α = 0.05. A) ±2.5706 B) ±2.7764 C) ±3.1634 D) ±3.4954 Answer: Difficulty: Difficult Keywords: t test on slope, critical value 18) Referring to Table 13-2, to test whether a change in price will have any impact on sales, what would be the critical values? Use α = 0.05. A) ±2.5706 B) ±2.7765 C) ±3.1634 D) ±3.4954 Answer: Difficulty: Difficult Keywords: t test on slope, critical value 19) Referring to Table 13-2, if the price of the candy bar is set at $2, the estimated mean sales will be A) 30. B) 65. C) 90. D) 100. Answer: Difficulty: Moderate Keywords: estimation of mean values EXTRA CREDIT: Chapter 14 Introduction to Multiple Regression TABLE 14-10 21) You worked as an intern at We Always Win Car Insurance Company last summer. You notice that individual car insurance premiums depend very much on the age of the individual and the number of traffic tickets received by the individual. You performed a regression analysis in EXCEL and obtained the following partial information: 22) Referring to Table 14-10, the proportion of the total variability in insurance premiums that can be explained by AGE and TICKETS is ________. Answer: Difficulty: Easy Keywords: coefficient of multiple determination, interpretation 23) Referring to Table 14-10, the proportion of the total variability in insurance premiums that can be explained by AGE and TICKETS after adjusting for the number of observations and the number independent variables is ________. Answer: Difficulty: Easy Keywords: adjusted r-square 24) Referring to Table 14-10, the standard error of the estimate is ________. Answer: Difficulty: Easy Keywords: standard error of estimate 25) Referring to Table 14-10, the estimated mean change in insurance premiums for every 2 additional tickets received is ________. Answer: Difficulty: Difficult Keywords: slope, interpretation 26) Referring to Table 14-10, the 99% confidence interval for the change in mean insurance premiums of a person who has become 1 year older (i.e., the slope coefficient for AGE) is 1.4061 ± ________. Answer: Difficulty: Moderate Keywords: slope, interpretation, confidence interval 27) Referring to Table 14-10, the total degrees of freedom that are missing in the ANOVA table should be ________. Answer: Difficulty: Easy Keywords: degrees of freedom 28) Referring to Table 14-10, the regression sum of squares that is missing in the ANOVA table should be ________. Answer: 1,670,569.3000 Difficulty: Easy Keywords: sum of squares 29) Referring to Table 14-10, the residual mean squares (MSE) that are missing in the ANOVA table should be ________. Answer: Difficulty: Easy Keywords: mean squares 30) Referring to Table 14-10, to test the significance of the multiple regression model, what is the form of the null hypothesis? A) H0 : β1 = 0 B) H0 : β2= 0 C) H0 : β1 = β2 = 0 D) H0 : β0 = β1 = β2 = 0 Answer: Difficulty: Easy Keywords: F test on the entire regression, form of hypothesis 31) Referring to Table 14-10, to test the significance of the multiple regression model, the value of the test statistic is ________. Answer: 16.2457 Difficulty: Easy Keywords: F test on the entire regression, test statistic 32) Referring to Table 14-10, to test the significance of the multiple regression model, the p-value of the test statistic in the sample is ________. Answer: Difficulty: Easy Keywords: F test on the entire regression, p-value 33) To explain personal consumption (CONS) measured in dollars, data is collected for INC: personal income in dollars CRDTLIM: $1 plus the credit limit in dollars available to the individual mean annualized percentage interest rate for borrowing for the APR: individual per person advertising expenditure in dollars by manufacturers in the ADVT: city where the individual lives SEX: gender of the individual; 1 if female, 0 if male A regression analysis was performed with CONS as the dependent variable and CRDTLIM, APR, ADVT, and GENDER as the independent variables. The estimated model was What is the correct interpretation for the estimated coefficient for GENDER? A) Holding the effect of the other independent variables constant, mean personal consumption for females is estimated to be $0.39 higher than males. B) Holding the effect of the other independent variables constant, mean personal consumption for males is estimated to be $0.39 higher than females. C) Holding the effect of the other independent variables constant, mean personal consumption for females is estimated to be 0.39% higher than males. D) Holding the effect of the other independent variables constant, mean personal consumption for males is estimated to be 0.39% higher than females. Answer: Difficulty: Easy Keywords: dummy variable, slope, interpretation TABLE 14-15 The superintendent of a school district wanted to predict the percentage of students passing a sixth-grade proficiency test. She obtained the data on percentage of students passing the proficiency test (% Passing), mean teacher salary in thousands of dollars (Salaries), and instructional spending per pupil in thousands of dollars (Spending) of 47 schools in the state. Following is the multiple regression output with Y = % Passing as the dependent variable, X1 = Salaries and X2 = Spending: 34) Referring to Table 14-15, which of the following is a correct statement? A) The mean percentage of students passing the proficiency test is estimated to go up by 2.79% when mean teacher salary increases by one thousand dollars. B) The mean teacher salary is estimated to go up by 2.79% when mean percentage of students passing the proficiency test increases by 1%. C) The mean percentage of students passing the proficiency test is estimated to go up by 2.79% when mean teacher salary increases by one thousand dollars holding constant the instructional spending per pupil. D) The mean teacher salary is estimated to go up by 2.79% when mean percentage of students passing the proficiency test increases by 1% holding constant the instructional spending per pupil. Answer: Difficulty: Moderate Keywords: interpretation, slope 35) Referring to Table 14-15, which of the following is a correct statement? A) 18.26% of the total variation in the percentage of students passing the proficiency test can be explained by mean teacher salary and instructional spending per pupil. B) 18.26% of the total variation in the percentage of students passing the proficiency test can be explained by mean teacher salary and instructional spending per pupil after adjusting for the number of predictors and sample size. C) 18.26% of the total variation in the percentage of students passing the proficiency test can be explained by mean teacher salary holding constant the effect of instructional spending per pupil. D) 18.26% of the total variation in the percentage of students passing the proficiency test can be explained by instructional spending per pupil holding constant the effect of mean teacher salary. Answer: Difficulty: Moderate Keywords: interpretation, coefficient of multiple determination 36) Referring to Table 14-15, which of the following is a correct statement? A) 14.57% of the total variation in the percentage of students passing the proficiency test can be explained by mean teacher salary and instructional spending per pupil. B) 14.57% of the total variation in the percentage of students passing the proficiency test can be explained by mean teacher salary and instructional spending per pupil after adjusting for the number of predictors and sample size. C) 14.57% of the total variation in the percentage of students passing the proficiency test can be explained by mean teacher salary holding constant the effect of instructional spending per pupil. D) 14.57% of the total variation in the percentage of students passing the proficiency test can be explained by instructional spending per pupil holding constant the effect of mean teacher salary. Answer: Difficulty: Moderate Keywords: interpretation, adjusted r-square 37) Referring to Table 14-15, what is the standard error of estimate? Answer: Difficulty: Easy Keywords: standard error of estimate 38) Referring to Table 14-15, predict the percentage of students passing the proficiency test for a school which has a mean teacher salary of 40,000 dollars, and an instructional spending per pupil of 2,000 dollars. Answer: Difficulty: Easy Keywords: prediction of individual values 39) Referring to Table 14-15, estimate the mean percentage of students passing the proficiency test for all the schools that have a mean teacher salary of 40,000 dollars, and an instructional spending per pupil of 2,000 dollars. Answer: Difficulty: Easy Keywords: estimation of mean values 40) Referring to Table 14-15, which of the following is the correct null hypothesis to test whether instructional spending per pupil has any effect on percentage of students passing the proficiency test, taking into account the effect of mean teacher salary? A) H0 : β0 = 0 B) H0 : β1 = 0 C) H0 : β2 = 0 D) H0 : β3 = 0 Answer: Difficulty: Easy Keywords: t test on slope, form of hypothesis