Using the dataset NutritionStudy, we calculate that the average number of grams of fat consumed in a day for the sample of n equals 315 US adults in the study is x Overscript bar EndScripts equals 77.03 grams with s equals 33.83 grams.
(a) Find a 99% confidence interval for the average number of fat grams consumed per day by US adults.
Round your answers to two decimal places.
The 99% confidence interval is to
(b) What is the margin of error?
Round your answer to two decimal places.
margin of error equals
(c) If we want a margin of error of only plus-or-minus 2.5, what sample size is needed?
Round your answer up to the nearest integer.
sample size equals