1. Construct the indicated confidence interval for the difference between population proportions p1-p2. Assume that the samples are independent and that they have been randomly selected.

In a random sample of 500 people aged 20-24, 22% were smokers. In a random sample of 450 people aged14% were smokers. Construct a 95% confidence interval for the difference between the population proportions p1- p2.

2. In a random sample of 360 women, 65% favored stricter gun control laws. In a random sample of 220 men, 60% favored stricter gun control laws. Test the claim that the proportion of women favoring stricter gun control is higher than the proportion of men favoring stricter gun control. Use a significance level of 0.05.

3. Test the indicated claim about the means of two populations. Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal. Use the P-value method.

A researcher wishes to determine whether people with high blood pressure can reduce their blood pressure, measured in mm Hg, by following a particular diet. Use a significance level of 0.01 to test the claim that the treatment group is from a population with a smaller mean than the control group.

treatment group

n1= 35

x1= 189.1

s1= 38.7

control group

n2= 28

x2= 203.7

s2= 39.2

4. Construct the indicated confidence interval for the difference between the two population means. Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal.

A researcher was interested in comparing the amount of time spent watching television by women and by men. Independent simple random samples of 14 women and 17 men were selected, and each person was asked how many hours he or she had watched television during the previous week. The summary statistics are as follows. Construct a 99% confidence interval forthe difference

between the mean amount of time spent watching television for women and the mean amount of time spent watching television for men.

women

x1=12.6hrs

s1=3.9 hrs

n1=14

men

x2=14.0hrs

s2=5.2hrs

n2=17

5.The two data sets are dependent. Findto the nearest tenth.

x 236 109 220 182 253 295 302

y 194 153 195 153 235 253 284

6.The differences between two sets of dependent data are 0.4, 0.24, 0.22, 0.26, 0.34. Find sd. Round to the nearest hundredth.

7.Assume that you want to test the claim that the paired sample data come from a population for which the mean difference is d= 0. Compute the value of the t test statistic. Round intermediate calculations to four decimal places as needed and final answers to three decimal places as needed.

x 8.1 5.2 5.4 8.9 4.4 12.1 8.9 6.2

y 6.3 4.9 6.5 4.2 4.8 6.8 5 4.5

8.Construct a confidence interval for d, the mean of the differences d for the population of paired data. Assume that the population of paired differences is normally distributed.

The table below shows the weights of 9 subjects before and after following a particular diet for two months. Construct a 99% confidence interval for the mean difference of the "before" minus "after" weights.

subject A B C D E F G H I

before 169 180 157 132 202 124 190 210 171

after 162 178 145 125 171 126 180 195 163

9. The table below shows the weights of seven subjects before and after following a particular diet for two months. Using a 0.01 level of significance, test the claim that the diet is effective in reducing weight.

subject A B C D E F G

before 178 167 194 154 174 156 194

after 171 158 192 159 160 158 182