Construct Confidence Interval for Data Sets Questions

1) Suppose you want to test the claim that μ1 = μ2. Two samples are randomly selected from each

population. If a hypothesis test is performed, how should you interpret a decision that rejects the null

hypothesis?

2) Construct a 90% confidence interval for μ1 – μ2. Two samples are randomly selected from normal

populations. The sample statistics are given below. Assume that σ21 = σ22.

n1 = 10 n2 = 12

x1 = 25 x2 = 23

s1 = 1.5 s2 = 1.9

3) Construct a 95% confidence interval for μ1 – μ2. Two samples are randomly selected from normal

populations. The sample statistics are given below. Assume that σ21 = σ22.

n1 = 8 n2 = 7

x1 = 4.1 x2 = 5.5

s1 = 0.76 s2 = 2.51

4) Data sets A and B are dependent. Find d.

A 36 32 53 49 37

B 34 30 31 41 28

5) Construct a 95% confidence interval for data sets A and B. Data sets A and B are dependent. Round to

the nearest tenth.

A 30 28 47 43 31

B 28 24 25 35 22

6) Construct a 99% confidence interval for data sets A and B. Data sets A and B are dependent. Round to

the nearest tenth.

A 5.8 6.8 8.7 5.7 5.8

B 8.2 7.1 7.0 6.9 8.3

7) Find the standardized test statistic, z, to test the claim that p1 < p2. The sample statistics listed below

are from independent samples.

Sample statistics: n1 = 550, x1 = 121, and n2 = 690, x2 = 195

8)) Find the weighted estimate, p, to test the claim that p1 < p2. Use α = 0.10. The sample statistics

listed below are from independent samples.

Sample statistics: n1 = 550, x1 = 121, and n2 = 690, x2 = 195

9) In a recent survey of gun control laws, a random sample of 1000 women showed that 65% were in favor

of stricter gun control laws. In a random sample of 1000 men, 60% favored stricter gun control laws.

Construct a 95% confidence interval for p1 − p2.

10) A random sample of 100 students at a high school was asked whether they would ask their father or

mother for help with a homework assignment in science. A second sample of 100 different students was

asked the same question for an assignment in history. Forty-three students in the first sample and 47

students in the second sample replied that they turned to their mother rather than their father for help.

Construct a 98% confidence interval for p1 − p2