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**7.3.9**** **

__ u__se technology and the given confidence level and sample data to find the confidence interval for the population mean u. Assume that the population does not exhibit a normal distribution.

Weight lost on a diet:

95% Confidence

n = 41

x = 3.0 kg

s = 5.4 kg

What is the confidence interval for the population mean u?

**7.3.10**

Listed below are the amounts of mercury (in PPM) found in tuna sushi sampled at different stores. The sample mean is 1.106 ppm and the sample standard deviation is 0.129 ppm. Use technology to construct a 90% confidence interval estimate of the mean amount of mercury in the population.

1.18 , 1.22, 1.13, 1.25, 1.04, 0.88, 1.04

What is the confidence interval estimates of the mean amount of mercury in the population?

**7.3.13**

A data set includes 110 body temperatures of healthy adults humans for which x – 98.0 degree F and a s = 0.74 degrees F. Complete parts (a) and (b) below.

A. What is the best point estimate of the mean body temperature of all healthy humans?

The best point estimate is _______ degree F. (Type an integer or a decimal).

**7.3.23**

In a study designed to test the effectiveness of magnets for treating back pain, 40 patients were given a treatment with magnets and also a sham treatment without magnets. Pain was measured using a scale from 0 (No Pain) to 100 (Extreme pain). After given the magnet treatments, the 40 patients had pain scores with a mean of 5.0 and a standard deviation of 2.8. After being given the sham treatment, the 40 patients had pain scores with a mean of 4.7 and a standard deviation of 2.4.

A. Construct the 99% confidence interval estimate of the mean pain score for patients given the magnet treatment.

What is the confidence interval estimate for the population mean u?

B. Construct the 99% confidence interval estimate of the mean pain score for patients given the sham treatment.

What is the confidence interval estimate for the population mean u?

A physician wants to develop criteria for determining whether a patient’s pulse rate is atypical, and she wants to determine whether there are significant differences between males and females. Use the sample pulse rates below:

A. Construct a 95% confidence interval estimate of the mean pulse rates for males.

B. Construct a 95% confidence interval estimate of the mean pulse rates for females.

An IQ test is designed so that the mean is 100 and the standard deviation is 14 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 90% confidence that the sample mean is within 2 IQ points of the true mean. Assume that o = 14 and determine the required sample size using technology. Then determine if this is reasonable sample size for a real world calculation.

In order to estimate the mean amount of time computer users spend on the internet each month, how many computers users must be surveyed in order to be 95% confident that your sample mean is within 15 minutes of the population mean? Assume that the standard deviation of the population of month time spent on the internet is 192 minutes. What is a major obstacle to getting a good estimate of the population mean? Use technology to find the estimated minimum required sample size.

using the simple random sample of weights of women from a data set, we obtain these sample statistics: n=40 and x = 152.97 lb. Research from other sources suggests that the population of weights of women has a standard deviation given by o = 32.72 lb.

a. find the best point estimate of the mean weight of all women

b. find 95% confidence interval estimate of the mean weight of all women