A manufacturer claims that the mean amount of juice in its 16 ounce bottles is 16.2 ounces. A consumer advocacy group wants to determine whether the mean amount is actually less than this. The mean volume of juice for a random sample of 70 bottles was 16.04 ounces with a standard deviation of 0.9 ounces. Find a 95% confidence interval to estimate the true mean amount of juice in these bottles.

Question

A manufacturer claims that the mean amount of juice in its 16 ounce bottles is 16.2 ounces.  A consumer advocacy group wants to determine whether the mean amount is actually less than this. The mean volume of juice for a random sample of 70 bottles was 16.04 ounces with a standard deviation of 0.9 ounces. Find a 95% confidence interval to estimate the true mean amount of juice in these bottles.

A) What is the sample mean?

B) Standard deviation?

C) How many standard deviations do we need to capture 95% estimate?

D) Margin of error?

PsyDAG · Answer

A, B) random sample of 70 bottles was 16.04 ounces with a standard deviation of 0.9 ounces. C) ± 2 SD D) Z = (score-mean)/SEm SEm = SD/√n