1. Use the normal distribution to approximate the desired binomial probability. Springfield reports that 76% of its residents rent their home. A check of 60 randomly selected residents shows that 49 of them rent their homes. Find the probability that among the 60 residents, 49 or more rent their homes.

• 0.1192
• 0.1166
• 0.1520
• 0.1903
• None of these

2. Given that the 91% confidence limits for ?? are 74 and 96, which of the following could possibly be the 92% confidence limits?

• 74 and 96
• 77 and 93
• 72 and 98
• 73 and 101
• None of these could be the 92% confidence limits.

3. In a Gallup poll of 700 randomly selected adults, 356 of them said that they were underpaid. Construct a 90% confidence interval estimate of the percentage of all adults who say that they are underpaid. Can we safely conclude that the majority of adults say that they are underpaid?

• 47.7% p
• 48.4% p
• 47.7% p
• 48.4% p

4. Find the minimum sample size needed to estimate the percentage of engineers who have a child. Use a 0.07 margin of error, use a confidence level of 99.8%, and use the results from a prior Harris poll that gave a confidence interval of (0.45, 0.54) for the proportion of engineers who have a child.

• 423
• 30
• 3
• 488
• None of these

5. A sample of 60 statistics classes yields a mean class size of xx = 18.1 students with a standard deviation of s = 8.4 students. The 99% confidence interval estimate for the population mean is:

• 15.21 students
• 15.31 students
• 15.51 students
• 16.29 students
• 16.32 students

6. What is the minimum sample size needed to estimate the mean age of books in a library to within 16 months with 99% confidence if the standard deviation of the ages is thought to be about 130 months?

• 361
• 19
• 439
• 21
• None of these

7. Captopril is a drug designed to lower systolic blood pressure. When subjects were tested with this drug, their systolic blood pressure readings were measured before and after drug treatment, with the results given below. Assume an approximately normal distribution, if necessary. Use the sample data to construct a 95% confidence interval for the mean difference between the before and after readings.

Subject	A	B	C	D	E	F
Before	174	150	150	204	161	194
After	150	154	179	154	146	145

• -7.1
• -14.7
• -7.1
• -7.8
• -6.2

8. A hypothesis test yields a test statistic of z = 1.55. Compute the P-value if this is a one-tailed test and if it is a two-tailed test.

• one-tailed P-value is 0.9394; and two-tailed P-value is 1.8788
• one-tailed P-value is 0.9394; and two-tailed P-value is 0.4697
• one-tailed P-value is 0.0606; and two-tailed P-value is 0.0303
• one-tailed P-value is 0.0606; and two-tailed P-value is 0.1212

9. When testing the claim that the mean of the differences is greater than zero, suppose you get a test statistic of t = 4.17 and a P-value of 0.0001. What should we conclude about the claim?

• There is not sufficient evidence to warrant rejection of the claim.
• There is not sufficient evidence to support the claim.
• There is sufficient evidence to support the claim.
• There is sufficient evidence to warrant rejection of the claim.

10. The manager of Riverside Bottling Corporation claims that her company is filling bottles with one quart (32 ounces) of juice. She randomly selects 38 of these bottles, measures their content, and obtains a mean of 31.78 oz. and a standard deviation of 0.81 oz.

Find the value of the test statistic and critical value(s) for testing the manager's claim at the ?? = 0.02 level.

• test statistic t = -1.674, critical values 2.129
• test statistic t = -1.674, critical values 2.431
• test statistic z = -1.674, critical values 2.054
• test statistic z = -1.674, critical values 2.326

11. A simple random sample of 39 four-cylinder cars and a simple random sample of 32 six-cylinder cars is obtained. When using the samples below to test the claim that the mean braking distance of four-cylinder cars is at least as long as the mean braking distances of six-cylinder cars, find the alternative hypothesis.

Four-cylinder	Six-cylinder
n1 = 39	n2 = 32
x1x1 = 138 ft	x2x2 = 139.8 ft
s1 = ft	s2 = ft

• H1:?1??2?0H1:?1-?2?0
• H1:?1??2
• H1:?1??2?0H1:?1-?2?0
• H1:?1??2>0

12.

A researcher would like to test the claim that the proportion of middle-aged smokers with a lung capacity under 3 liters is less than the proportion of senior citizen nonsmokers with a lung capacity under 3 liters. A random sample of 32 middle-aged smokers had 25 with lung capacities under 3 liters, and a random sample of 32 senior citizen nonsmokers had 17 with lung capacities under 3 liters. These two independent samples will be used in a hypothesis test of this claim. Which test statistic formula should be used for this test? dd 0*? V's Ot {531E2){#1.u2) 82 5% 1711+n2 Oz li152)l#1.u2) 0? 03 7.7%: Oz (131 132)_lP1P2) 0 None of the above