Mrs. Gallas wanted to estimate the average weight of an Oreo cookie to determine if the average weight was less than advertised. She selected a random sample of 30 cookies and found the weight of each...

Mrs. Gallas wanted to estimate the average weight of an Oreo cookie to determine if the
average weight was less than advertised. She selected a random sample of 30 cookies and
found the weight of each cookie (in grams). The mean weight was = 11.1921 grams with a
standard deviation of sx = 0.0817 grams. Make a 95% confidence interval to estimate the true
mean weight of an Oreo.

1. What is the formula for calculating the standard deviation of the sampling distribution of x?

2.What condition must be met to use this formula? Has it been met?