146CHAPTER 8HYPOTHESIS TESTING: Z AND t TESTSa b c1 2SPREADSHEET SOLUTIONPooled Variance t Test for the Differences in Two Arithmetic MeansWhen using sample data: Select Tools Data Analysis, and in the Data Analysis dialog box select t-Test: Two-Sample Assuming Equal Variances and click OK. In the t-Test dialog box, enter the group 1 cell range as the Variable 1 Range and enter the group 2 cell range as the Variable 2 Range. Enter 0 as the Hypothesized Mean Difference and, if appropriate, check Labels. Enter 0.05 as the Alpha value, select the New Worksheet Ply option, and click OK. Results appear on a new worksheet. (See Appendix D.3 for more information about the Data Analysis feature.) When using sample statistics: Download and open the Chapter 8 Pooled T.xls Excel file into which you can enter the values for the hypothesized difference, the level of significance, and the sample size, sample mean, and sample standard deviation for each group. Already entered into the worksheet as an example are the data of Worked-out Problem 1.equation blackboard(optional)The Worked-out Problems use the pooled variance t test for the difference between the population means of two independent groups. You need the subscripted symbols for the sample means, X1 and X 2, the sample size, n, and population means, 1 and 2, as well as the symbol for the pooled estimate of the variance, S 2 , to express the t test statistic p calculation as an equation. To write the t test statistic equation, you first define the symbols for the equation for the pooled estimate of the population variance: S2 = p2 2 (n 1 �1)S1 + (n 2 �1)S 2 (n 1 �1) + (n 2 �1)sted intere in math(continues)
