# Confidence interval for population proportion and mean

* 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.

x1 = 57, n1 = 95 and x2 = 84, n2 = 96; Construct a 98% confidence interval for the difference between population proportions p1 - p2.

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Construct the indicated confidence interval for the difference between the two population means. Assume that the two samples are independent and that they have been randomly selected.

A researcher wishes to determine whether people with high blood pressure can reduce their blood pressure by following a particular diet. Use the sample data below to construct a 99% confidence interval for u1 - u2 where u1 and u2 represent the mean for the treatment group and the control group respectively.

n1 = 85 n2 = 75

1 = 189.1 2 = 203.7

s1 = 38.7 s2 = 39.2

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Question 3:

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.

x1 = 29, n1 = 60 and x2 = 47, n2 = 85; Construct a 95% confidence interval for the difference between population proportions p1 - p2.

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Construct the indicated confidence interval for the difference between the two population means. Assume that the two samples are independent and that they have been randomly selected.

Independent samples from two different populations yield the following data:

1 = 619, = 189, The sample size is 235 for both samples. Find the 90 percent confidence interval for

a. 430 < μ1 - μ2 < 430

b. 420 < μ1 - μ2 < 440

c. 426 < μ1 - μ2 < 434

d. 425 < μ1 - μ2 < 435

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Determine the decision criterion for rejecting the null hypothesis in the given hypothesis test; i.e., describe the values of the test statistic that would result in rejection of the null hypothesis.

We wish to compare the means of two populations using paired observations. Suppose that:

d = 3.125, Sd = 2.911, and n = 8, and that you wish to test the following hypothesis at the 10 percent level of significance:

H0: μd = 0 against H1: μd > 0.

What decision rule would you use?

Reject?

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Compute the test statistic used to test the null hypothesis that p1 = p2.

n1 = 179 n2 = 173

x1 = 65 x2 = 59

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Compute the test statistic used to test the null hypothesis that p1 = p2.

A report on the nightly news broadcast stated that 14 out of 140 households with pet dogs were burglarized and 21 out of 217 without pet dogs were burglarized.

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Assume that you want to test the claim that the paired sample data come from a population for which the mean difference is μd = 0. Compute the value of the t test statistic.

x| 30 34 19 25 26 30 29 30

y| 28 30 25 25 27 35 29 29

a. t = 0.690

b. t = -1.480

c. t = -0.185

d. t = -0.523

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Assume that you want to test the claim that the paired sample data come from a population for which the mean difference is μd = 0. Compute the value of the t test statistic.

a. t = 2.391

b. t = 0.845

c. t = 6.792

d. t = 0.998

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Assume that you want to test the claim that the paired sample data come from a population for which the mean difference is μd = 0. Compute the value of the t test statistic.

x| 7 2 7 3 10

y| 4 4 3 4 5

a. t = 1.292

b. t = 0.415

c. t = 0.578

d. t = 2.890

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Test the indicated claim about the variances or standard deviations of two populations. Assume that the populations are normally distributed. Assume that the two samples are independent and that they have been randomly selected.

A random sample of 16 women resulted in blood pressure levels with a standard deviation of 21.8 mm Hg. A random sample of 17 men resulted in blood pressure levels with a standard deviation of 19.5 mm Hg. Use a 0.025 significance level to test the claim that blood pressure levels for women have a larger variance than those for men.

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Find sd.

Consider the set of differences between two dependent sets: 84, 85, 83, 63, 61, 100, 98. Round to the nearest tenth.

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Find the number of successes x suggested by the given statement.

Among 870 people selected randomly from among the eligible voters in one city, 52.3% were homeowners

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Find the appropriate p-value to test the null hypothesis, H0: p1 = p2, using a significance level of 0.05.

n1 = 100 n2 = 140

x1 = 41 x2 = 35

a. .4211

b. .0086

c. .0512

d. .0021

#### Solution Summary

The solution gives the details of construction of confidence interval for mean and population proportion.