2) An Industrial/Organizational Psychologist plans a study on cortisol levels (a measure of stress) in corporateCEOS before versus after a critical meeting to avoid a hostile takeover by a larger company. She measurescortisol levels twice in each of the 24 randomly selected CEOS from Silicon Valley, once before and once afterthe meeting. She predicts that cortisol levels after the meeting will be different relative to before. t =n(E D²)- (E D)*n - 1n = number of pairs of scores (for example, if 8 people are measured at t1 and t2, df = 8-1 = 7)D= the difference between each pair of scoresED= the sum of the differences(ED²) = the sum of the squares of the differences(ED)²= the sum of the differences squaredt score: Independent Samples t-test (degrees of freedom = (n1 – 1) + (n2 – 1))n, - 1п, - 1X= mean of first group (sample)X= mean of second group (sample)s²1= sample variance of first groups?2 = sample variance of second groupn1 = number of subjects (or observations) in the first groupn = number of subjects in second groupBe careful about computing the denominator; pay attention to whether you are working with sample variances or standarddeviations to make sure your computations are correct.One Way ANOVA (see ANOVA table for degrees of freedom)Between Groups Sum of Squares: Subtract the grand mean from each group mean, square the deviation,multiply by n in each group and add the values together.SSu = En (X, - Xn = the number of subjects or observations in a groupX, = the mean for any group (1 through n) of subjectsXg = the overall, or grand, mean for all subjects or observationsWithin Groups Sum of Squares: Subtract each group's mean from the individual scores and add them all up.SSWΣΣ (X - XX = any single score within any particular groupX „= the mean of any particular groupng = number of groupsN = total # of subjects/observationsSdfMSFMS, =SS, / dfgTreatmentdf, =F =(Between= B)ng-1MS /MSWError (Within= W) SSwdfw =N - nGMSw=SSw/ dfwTotalSSTotal =SS, + SSwdfrotal=N -1 =df,+ dfw

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T test are usually used to compare estimates about population mean
1.  Independent T test for single…