STAT151 Lecture Notes - Lecture 21: Point Estimation, Statistical Hypothesis Testing, Pooled Variance

• School: University of Alberta
• Department: Statistics
• Course: STAT151
• Professor: Sean Graves

Document Summary

We want to make an inference about the value of 1 2 based on the point estimate y1 y 2 . To do this, let n1 be the size of sample 1 , n2 be the size of sample 2. s1 be the standard deviation of sample 1 , s2 be the standard deviation of sample 2. Y1 be the mean of sample 1 , y2 be the mean of sample 2. A confidence interval for 1 2 is given by: point estimate margin or error. Y1 y 2 t (se) , where t depends on the confidence level and df is safely min {n1 , n2} and se = s1 n1. The actual formula for df is hideous, you can check it out on page 602 of your textbook. A test is done on a herd of 25 milking cows to compare milk production levels of field- wilted alfalfa fed cows versus dehydrated alfalfa-fed cows.