Chapter 8 Confidence Intervals OBJECTIVES Calculate and interpret confidence intervals for estimating a population mean...

 

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Chapter 8 Confidence Intervals OBJECTIVES • Calculate and interpret confidence intervals for estimating a population mean and a population proportion. . Interpret the Student's t probability distribution as the sample size changes. • Discriminate between problems applying the normal and the Student's t distributions. Calculate the sample size required to estimate a population mean and a population proportion given a desired confidence level and margin of error. 1. Suppose you have a data set (population data) whose mean is unknown. To find the mean, you select a random sample of size 50. How would you make a statistical statement about the mean of the population when you have found that the mean of your sample is 40 (point estimate of the mean (parameter) of the population)? The mean of the population is 40. (least statistical) The mean of the population seems to be 40. The mean of the population is about 40. The mean of the population seems to be around 40. • I am quite confident that the mean of the population is around 40. . I am 95 % sure that the mean of the population is between 38 and 42. (most statistical) 2. The 95 % in the above example is called the (more precisely 95 % 3. The confidence interval can be written in the form (point estimate- point estimate + So, the margin of error of this example is 2. *************** ******* and the interval 38 to 42 the ..) for the population mean. .). 4. One type of questions that we will deal with in this chapter is the ones of finding the confidence interval for the mean of the population when given a confidence level and a sample. Chapter 8 Confidence Intervals OBJECTIVES • Calculate and interpret confidence intervals for estimating a population mean and a population proportion. . Interpret the Student's t probability distribution as the sample size changes. • Discriminate between problems applying the normal and the Student's t distributions. Calculate the sample size required to estimate a population mean and a population proportion given a desired confidence level and margin of error. 1. Suppose you have a data set (population data) whose mean is unknown. To find the mean, you select a random sample of size 50. How would you make a statistical statement about the mean of the population when you have found that the mean of your sample is 40 (point estimate of the mean (parameter) of the population)? The mean of the population is 40. (least statistical) The mean of the population seems to be 40. The mean of the population is about 40. The mean of the population seems to be around 40. • I am quite confident that the mean of the population is around 40. . I am 95 % sure that the mean of the population is between 38 and 42. (most statistical) 2. The 95 % in the above example is called the (more precisely 95 % 3. The confidence interval can be written in the form (point estimate- point estimate + So, the margin of error of this example is 2. *************** ******* and the interval 38 to 42 the ..) for the population mean. .). 4. One type of questions that we will deal with in this chapter is the ones of finding the confidence interval for the mean of the population when given a confidence level and a sample.

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Solution 1 Confidence Interval Point Estimate Margin of Error It is ... View the full answer