Question

A baker wants to know if refrigerating cookie dough before baking stops the dough from spreading out too thin in the oven (i.e., creates thicker cookies). To test this he bakes 36 refrigerated and 36 non-refrigerated cookies and measures how wide they are once baked. For the refrigerated cookies M = 3.66, SD = 1 and for the non-refrigerated cookies M = 4.14, SD = 0.84. What is the 95% confidence interval for the population difference between refrigerated and non-refrigerated cookie width?

What is the critical value?

Depending on the appropriate CI formula, calculate whichever is requested by the formula: the SEM, est. SEM, or est SEdiff

What is the lower bound CI?
What is the upper bound CI?

Based on the CI containing/not containing 0, what can you conclude about the null hypothesis?

Answer 1

Given data is

For Refrigerated cookies

sample size =n1=36