Question

A soft drink manufacturer wishes to know how many soft drinks adults drink each week. They want to construct a 95% confidence interval with an error of no more than 0.08. A consultant has informed them that a previous study found the mean to be 3.1 soft drinks per week and found the variance to be 0.49. What is the minimum sample size required to create the specified confidence interval? Round your answer up to the next integer.

Answer 1

A Soft drink manufacturer wishes to know how many soft drinks adults drink each week. The variance of the previous studies is

We want to find the minimum sample size required to create the the 95% confidence intervals with an error of no more than 0.08, the sample size is obtained by

E=0.08

. Buy using z table z0.025=1.96

Squaring both sides

Thus the required sample size is n=294