Download The principal of a middle school claims that the mean test score of

The principal of a middle school claims that the mean test score of the seventh-graders at
his school is higher than 72.1. You wish to test this claim at the 0.05 level of significance.
The mean score for a random sample of 100 seventh-graders is 75.7 with a standard
deviation of 15.2.
What criterion would be used for rejecting the null hypothesis, given the claim that µ 72.1?
Assume that the standard deviation of the population,sigma, is known.
Answer
Reject Ho if test statistic > 1.645.
Reject Ho if test statistic > 1.96 or < -1.96.
Reject Ho if test statistic > 1.96.
Reject Ho if test statistic < 1.645.
6 points
Question 2 A chicken farmer in Grayslake claims that his chickens have a mean weight of
58 ounces. The farmer takes a random sample of 36 chickens and finds a mean weight of
59.2 ounces and a standard deviation of 3 ounces. In a hypothesis test, what criterion would
be used for rejecting the farmer's claim at the 10 percent level of significance?Assume that
the standard deviation of the population, sigma, is known.
Answer
Reject Ho that µ = 58 ounces if test statistic > 1.28 or < -1.28.
Reject Ho that µ = 58 ounces if test statistic > 1.28.
Reject Ho that µ = 58 ounces if test statistic > 1.645 or < -1.645.
Reject Ho that µ = 58 ounces if test statistic > 1.645.
6 points
Question 3 What is the margin of error, given that 95% confidence interval;
n = 12; = 55.7, and s = 6.7?
Answer
5.108
3.831
4.257
3.193
6 points
Question 4
A laboratory tested 12 chicken eggs and found that the mean amount of cholesterol was 224
milligrams with s = 18.5 milligrams. What is the 95 percent confidence interval for the true
mean cholesterol content of all such eggs?
I. 214.4 < µ < 233.6
II. 217.7< µ < 230.3
III. 213.5 < µ < 234.5
IV. 212.2 < µ < 235.8
Answer
Please refer to answer choice I above.
Please refer to answer choice II above.
Please refer to answer choice III above.
Please refer to answer choice IV above.
6 points
Question 5
Find the value of the linear correlation coefficient r. The paired data below consist of the
temperatures on randomly chosen days and the amount a certain kind of plant grew (in
millimeters):
Answer 0.256 -0.210 0 0.196 6 points
I need the data here
Question 6 Use the margin of error, confidence level, and standard deviation s to find the
minimum sample size required to estimate an unknown population mean µ: Margin of
error: $130, confidence level: 99%, s = $501.
Answer
57
1
50
99
6 points
Question 7
Assume that X has a normal distribution. The mean is 137.0 and the standard deviation is
5.3. What is the probability that X is between 134.4 and 140.1?
Answer 0.4069 0.8138 1.0311 0.6242 6 points
Question 8
If Z is a standard normal variable, what is the probability P (Z > 0.59)?
Answer 0.7224 02224 02776 02190 6 points
Question 9 A drug company claims that over 70% of all physicians recommend their drug.
1200 physicians were asked if they recommend the drug to their patients. 45.00% said yes.
Ho: p = 0.7. Confidence level: 95%. What is the value of the appropriate test statistic used
to test the null hypothesis?
Answer
-17.01-24.57 -37.80 -18.90 6 points
Question 10 Identify the null hypothesis Ho and the alternative hypothesis H1. A researcher
claims that the amounts of acetaminophen in a certain brand of cold tablets have a standard
deviation different from the = 3.3 mg claimed by the manufacturer.
Ho: s ? l 3.3 mg, H1: s = 3.3 mg
II. Ho: s = 3.3 mg, H1: s ?3.3 mg
III. Ho: s = 3.3 mg, H1: s ? 3.3 mg
IV. Ho: s = 3.3 mg, H1: s > 3.3 mg
Answer Please refer to answer choice I above. Please refer to answer choice II
above Please refer to answer choice III above Please refer to answer choice IV
above 6 points
Answer: H0: s=3.3 H1: s≠3.3
Question 11 The principal of a middle school claims that test scores of the
seventh-graders at his school vary less than the test scores of the seventh-graders
at a neighboring school, which have variation described by sigma = 14.7.
Assuming that a hypothesis test of the claim has been conducted and that the
conclusion is to reject the null hypothesis, state the conclusion in nontechnical
terms Answer
There is sufficient evidence to support the claim that the standard deviation is
greater than 14.7.
There is sufficient evidence to support the claim that the standard deviation is
less than 14.7.
There is not sufficient evidence to support the claim that the standard deviation
is less than 14.7.
There is not sufficient evidence to support the claim that the standard deviation
is greater than 14.7. 6 points
Question 12 What is the margin of error for the 95% confidence interval used to
estimate the population proportion, given that n = 260 and x = 70? Answer
0.0539 0.0566 0.0485 0.0647 6 points
Question 13 Use the given level of confidence and sample data to construct a
confidence interval for the population proportion p: n = 143, x = 92; 90 percent.
Answer
0.576 < p< 0.710
0.580 < 0.706
0.574 < 0.706
0.559 < p< 0.687 6 points
Question 14 What is the value of the linear correlation coefficient r? Answer
0 -0.632 0.632 0.562 6 points
I need the data here
Question 15 Scores on an English test are normally distributed with a mean of
35 and a standard deviation of 7.4. What is the score that separates the top 59%
from the bottom 41%? Answer 30.6 36.7 39.4 33.3 6 points
Question 16 Do one of the following, as appropriate: Find the critical value ,
find the critical value , or state that neither the normal nor the t distribution
applies. 95% level of significance; n = 11; sigma s is known; population appears
to be very skewed. I. = 1.96 II. = 2.228 III. Neither the normal nor the t
distribution applies. IV. = 1.81 Answer Please refer to answer choice I above.
Please refer to answer choice II above. Please refer to answer choice III above.
Please refer to answer choice IV above. 6 points
Question 17 Assume that the data has a normal distribution and the number of
observations is greater than fifty. Also assume that the standard deviation of the
population, s, is known. Find the critical value or values used to test a null
hypothesis: a = 0.03; H1 is µ < 290. Answer 1.88 ±2.17 ±1.88 -1.88 6 points
Question 18 Find the critical value or values for the given hypothesis, sample
size, and significance level. Assume that the standard deviation of the
population, s, is unknown. H1: µ > 3.74, n = 13, a = 0.01.
Answer -2.650 2.650 2.681 -2.681 6 points
Question 19 Use the confidence level and sample data to find the margin of
error E: Systolic blood pressures for women aged 18-24: 94% confidence; n =
100, = 113.8 mm Hg, sigma s = 12.8 mm Hg.
Answer 2.4 mm Hg 2.1 mm Hg 10.0 mm Hg 52.5 mm Hg 6 points
Question 20 Use the confidence level and sample data to find the margin of
error E: The duration of telephone calls directed by a local telephone company:
sigma s = 3.7 minutes, n = 540, 92 percent confidence.
Answer 0.012 minutes 0.006 minutes 0.279 minutes 0.091 minutes 6 points
Question 21 A population is normally distributed with a standard deviation
sigma = 349. We wish to test the hypotheses Ho: µ = 66,818; H1 = µ > 66,818.
A 123-item sample has a mean = 66,399.2. What is the value of the test
statistic?
Answer -0.11 4233.38 -13.31 -1188.3 6 points
Can you check the options ¿
Question 22 What is the minimum sample size you should use to assure that
your estimate of will be within the required margin of error around the
population p? Margin of error: 0.04; confidence level: 90%; from a prior study,
is estimated by 0.20.
Answer 240 271 11 813 6 points
Question 23 What is the minimum sample size you should use to assure that
your estimate of will be within the required margin of error around the
population p? Margin of error: 0.007; confidence level: 99%; are unknown.
Answer 184 33,830 135,319 541,276 6 points
Question 24 270 randomly selected light bulbs were tested in a laboratory, 98
lasted more than 500 hours. Find a point estimate of the true proportion of all
light bulbs that last more than 500 hours. Answer 0.359 0.266 0.363 0.637 6
points Question 25 The following confidence interval is obtained for a
population proportion, p: 0.746 < p < 0.782. What is the margin of error, E?
Answer 0.019 0.018 0.036 0.764