The makers of weight loss product are interested in estimating the mean weight loss for users of their product. To do this, they have selected a random sample of n = 9 people and have provided them with a supply of the product. After six months, the nine people had an average weight loss of 15.3 pounds with a standard deviation equal to 3.5 pounds. The upper limit for the 90 percent confidence interval estimate for the population mean is approximately 17.47 pounds.

Question

Quizplus · Accepted Answer

Given the sample size (n = 9), sample mean ($\bar{x}$ = 15.3), sample standard deviation (s = 3.5), and confidence level (90%), the upper limit of the confidence interval can be calculated using the t-distribution (due to the small sample size) and the formula for the confidence interval. The calculation involves finding the appropriate t-value for the degrees of freedom (n-1 = 8) and the specified confidence level, then computing the margin of error by multiplying the t-value by the standard error of the mean (s/√n). Adding this margin of error to the sample mean gives the upper limit of the confidence interval, which can indeed approximate to 17.47 pounds, making the statement true.

The Makers of Weight Loss Product Are Interested in Estimating