Question

A sample of 26 paired observations generates the following data: d−d− = 1.0 and s2DsD2 = 3.4. Assume a normal distribution. (You may find it useful to reference the appropriate table: z table or t table)

a. Construct the 99% confidence interval for the mean difference μ_D. (Round intermediate calculations to at least 4 decimal places and final answers to 2 decimal places.)

Confidence interval is

to

Answer 1

Date: 05/01/2020 Answer a) A 99% confidence interval for the mean difference is, First, compute t-critical value then find confidence interval. The t critical value is, The sample size is small and two-tailed test. Look in the column headed a = 0.01 and the row headed in the t distribution table by using degree of freedom is, d.f.=n-1 = 26 – 1 = 25 The t critical value is 2.787.

99% C.I. = X ±t, x sa/n =1.0±2.787x/3.40/26 =1.00 ±1.01 = -0.01 to 2.01 A 99% confidence interval for the mean difference is -0.01 to 2.01