Question

Find the 95% confidence interval for estimating μd based on these paired data and assuming normality. (Give your answers correct to one decimal place.) Before 43 42 67 54 59 55 After 42 50 34 54 30 58 Lower Limit Upper Limit

Answer 1

Using excel to find the mean difference and standard deviation of the difference

Difference = After - Before

Mean is calculated using AVERAGE function and standard deviation is calculated using STDEV.S function

sample size is n = 6

degree of freedom = n-1 =6-1 = 5

alpha level = 1 -confidence level = 1 - 0.95 = 0.05

t critical = T.INV.2T(alpha,df)

= T.INV.2T(0.05,5)

= 2.571

Confidence interval =