Need some help A supermarket is interested in finding out wh

Need some help!!!

A supermarket is interested in finding out wheather the mean weekly sales volume of Coca-Cola are the same when the softdrinks are displayed on the top shelf and when they are displayed on the bottom shelf. Ten stores are randomly selected from the supermaket chain with 5 stores using the top shelf display and 5 stores using the bottom shelf display. Assume that the samples are normally distributed with equal population variances. Refere to the sales volume data in the table below, What are the critical values using a level of significance alpha=.01?

    a. +2.7638 and -2.7638
    b. +2.8965 and -2.8965
    c. +3.3554 and -3.3554
    d. +4.5407 and -4.5407

Solution

As this is a two tailed test of significance 0.01, with

df = n1 + n2 - 2 = 8,

then using a table/technology,

tcrit =-3.3554 and 3.3554 [OPTION C]