Question

1. You want to estimate the mean weightloss of people one year after using the Atkins diet. How many dieters must be surveyed if we want to be 95% confident that the sample mean weight loss is within 25 lb of the true population mean? Assume that the population standard deviation is known to be 10.6 11b

Answer 1

Here

Significance level is α = 0.05, margin error E = 0.25, σ = 10.6 ani ficance level as a

The critical value for the significance level α=0.05 is z_c = 1.96 The following formula is used to compute the minimum sample size required to estimate the population mean within the required margin of error:

4,0) 2 1.96 × 10.6 0.25 - 6906.02

Therefore, the sample size needed to satisfy the condition , and it must be an integer number, we conclude that the minimum required sample size is n = 6907.

n >6906.02