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AGB 360 - AGRIBUSINESS STATISTICS Multiple Choice Questions Below: Question 1 1 points Save A range of values constructed from sample data so that the population parameter occurs within that range at a specified probability is A. the population parameter. B. the mean of the population C. a confidence interval. D. a point estimate. Question 2 1 points Save The probability that an interval estimates contains the value of the population parameter is indicated by A. the degrees of freedom. B. the confidence level. C. the precise value of the population mean U D. the degrees of freedom minus 1. Question 3 1 points Save The width of a confidence interval is called the A. the standard error B. the sampling error C. the margin of error D. the error of confidence Question 4 1 points Save In general, higher confidence levels result in A. wider confidence intervals B. narrower confidence intervals C. a smaller standard error D. unbiased estimates Question 5 1 points Save All things being equal, as the sample size increases, the margin of error A. widens B. narrows C. stays the same D. None of the above Question 6 1 points Save The t distribution is a family of continuous distribution, with many similarities to A. the confidence interval. B. the population parameter. C. the standard normal distribution. D. the mean of the population. Question 7 1 points Save The t distribution is used when the population is normal, the population standard deviation is unknown and A. the sample contains less than 30 observations. B. the population standard deviation is known. C. the point estimate is known. D. the mean of the population is unknown. Question 8 1 points Save The finite population correction factor may be used to adjust the margin of error of a C.I. for the population mean or the margin of error of a C.I. for the population proportion when: A. the sample constitutes more than 5% of the finite population. B. the sample constitutes less than 5% of the finite population. C. the sample is larger than the finite population. D. the finite population cannot be estimated. Question 9 1 points Save The fraction, ratio, or percent indicating the part of the population having a particular trait of interest is A. a confidence interval. B. the population mean. C. the population proportion. D. a point estimate. Question 10 1 points Save The distribution of the sample proportion is approximated by the normal distribution when: A. n is less than 30. B. (as in a binomial distribution) π is less than 5. C. (as in a binomial distribution) Both nπ and n(1-π) are greater than 5. D. Standard Deviation is given. Question 11 1.5 points Save In order to estimate the average time spent on the computer terminals per student at a local university, data were collected for a sample of 81 business students over a one-week period and the sample mean equals 9 hours. Assume the population standard deviation is 1.8 hours. The 95% confidence interval for the average time spent on the computer at this university is: A. 7.04 to 110.96 hours per week B. 7.36 to 10.64 hours per week C. 7.80 to 10.20 hours per week D. 8.61 to 9.39 hours per week Question 12 1 points Save Situation 1: It is known that SAT scores are normally distributed. A "small" random sample of 26 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240. If we want to construct a 95% confidence interval for the average SAT score of the population, the degrees of freedom for reading the critical values of the "t" statistic is A. 23 B. 24 C. 25 D. 26 Question 13 1.5 points Save Refer to situation 1: The 95% confidence interval for the SAT scores is A. 1340.06 to 1459.94 B. 1307.75 to 1492.5 C. 1303.04 to 1496.96 D. 1400 to 1600 Question 14 1.5 points Save A random sample of 1000 registered voters was taken. Four hundred fifty of the people in the sample favored Candidate P. Develop a 95% confidence interval of the population proportion of registered voters who favor Candidate P A. 0.419 to 0.481 B. 0.40 to 0.50 C. 0.45 to 0.55 D. 1.645 to 1.96 Question 15 1.5 points Save An agribusiness temp-worker company needs to calculate a 95% confidence interval estimate for the average daily number of workers that they hire. Assuming that the company reports that the standard deviation is 200 temp-workers per day, how many days does the firm needs to sample so that the margin of error of the 95% C.I. will be 39.2 temp-workers or less? A. need to have a sample size of at least 40 days B. need to have a sample size of at least 100 days C. need to have a sample size of at least 1000 days D. None of the above Question 16 1 points Save An assumption made about the value of a population parameter is called a A. conclusion B. hypothesis C. confidence D. significance Question 17 1 points Save In hypothesis testing, the status quo, the state of nature, the "innocent until proven guilty" assumption made about the value of the population parameter is A. the alternative hypothesis. B. the null hypothesis. C. either the null or the alternative. D. None of these alternatives is correct. Question 18 1 points Save In hypothesis testing, committing the error of rejecting a true null hypothesis is A. a Type I error, denoted a B. a Type II error, denoted B C. Committed when not enough information is available. D. None of the above. Question 19 1 points Save The level of significance of a hypotheses test is the A. maximum allowable probability of committing a Type II error B. maximum allowable probability of committing a Type I error C. same as the confidence level D. same as the p-value Question 20 1 points Save The p-value is a probability that measures the support (or lack of support) for the A. null hypothesis B. alternative hypothesis C. sample statistic D. None of the above Question 21 1 points Save When the p-value approach is used for hypothesis testing, the null hypothesis is rejected if A. p-value < or = to a B. a < p-value C. p-value > or = to a D. p-value = a Question 22 1.5 points Save Situation 2: Customers start to get upset after 3 minutes of waiting at the checkout and the store looses money if too many cashiers are assigned. Therefore, management wants to determine, at α = 0.05 level, whether or not the average waiting time of all customers is significantly different than 3 minutes. The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes with a standard deviation of 0.5 minutes. The correct set of hypotheses for the test is A. Ho: u < 3 Ha: u < or equal to 3 B. Ho: = 3 Ha: does not equal 3 C. Ho: u does not equal 3 Ha: u does equal 3 D. Ho: u greater than or equal to 3 Ha: u < 3 Question 23 1.5 points Save Refer to situation 2: Find the critical value for this test (hint: check α level and whether is a one-tailed or two-tailed test) A. 1.645 B. 1.96 C. 2.00 D. 0.056 Question 24 1.5 points Save Refer to situation 2: Calculate the test statistic A. 1.645 B. 1.96 C. 2.00 D. 0.056 Question 25 1.5 points Save Refer to situation 2: Using the critical value approach, our conclusion is that the A. average waiting time is significantly different than 3 minutes B. average waiting time is not significantly different than 3 minutes C. average waiting time is significantly less than 3 D. None of the above Question 26 1.5 points Save Situation 3: Evaluate the situation below. For a one-tailed test (upper tail) and a sample size of 26 at the 5% significance level, the appropriate t critical value is A. 1.706 B. -2.06 C. -1.708 D. 1.708 Question 27 1.5 points Save Refer to situation 3: The test statistic is A. 2.33 B. 1.955 C. -2.33 D. -1.955 Question 28 1.5 points Save Refer to situation 3: Using the critical value approach, it can be concluded that the mean of the population is A. significantly greater than 20 B. not significantly greater than 20 C. significantly less than 20 D. None of the above Question 29 1.5 points Save Situation 4: We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly greater than 80%. Ho: π less than or equal to .80 Ha: π > .80 A random sample of 100 people was taken. Eighty-five of the people in the sample favored Candidate A. The test statistic for this hypothesis of the population proportion equals A. 0.80 B. 0.05 C. 1.25 D. 2.00 Question 30 1.5 points Save Refer to situation 4: Based on the test statistic you just calculated, the p-value is A. 0.2112 B. 0.05 C. 0.025 D. 0.1056 Question 31 1.5 points Save Refer to situation 4: Based on the p-value you just calculated, at the α = 0.05 confidence level, it can be concluded that the proportion of the population in favor of candidate A A. the population proportion is significantly greater than 80% B. the population proportion is not significantly greater than 80% C. the population proportion is significantly greater than 85% D. the population proportion is not significantly greater than 85%