Question

The following table contains information on matched sample values whose differences are normally distributed. (You may find it useful to reference the appropriate table: z table or t table) Number Sample 1 16 Sample 2 21 10 12 WN 00 O a. Construct the 90% confidence interval for the mean difference up. (Negative values should be indicated by a minus sign. Round intermediate calculations to at least 4 decimal places and final answers to 2 decimal places.) Confidence interval is to

Answer 1

S. No diff:(d)=x1-x2 sample 1 16 sample 2 21 -5 25.00 12 10 4.00 23 24 -1 1.00 20 21 -1 1.00 16.00 17 21 -4 15 16 -1 1.00 17 19 -2 4.00 25.00 17 22 -5 total Id=-17 zd2=77 -2.1250 mean dbar= degree of freedom =n-1 7.000 Std deviaiton S,=v(Id²-(zd)*In)l{n-1) = 2.416 std error=Se-SpNn= 0.8543

for 90% CI; and 7 degree of freedom, value of t=			1.895
therefore confidence interval=sample mean -/+ t*std error
margin of errror          =t*std error=		1.619
lower confidence limit                     =		-3.744
upper confidence limit                    =		-0.506

from above 90% confidence interval =-3.74 to -0.51