Question

CRI 4377 3) Find the variance for ench group Assignment Chapter 7 Testiny Differences Hetween Meuns (the first llull) Name: 21) peints tatul 4) Find the Standard Error of the difference Between means 1. Research consistently shows that lack of self-control, a strong conclate of antisocial behavior, is greater in malcs than in fcanales. A researcherandsally surveys 10 boys and 10 girls from a middle school and wants to find out wls the boys do, in fact, report lower levels of self-control. The concept, self-control, is measured by a well-established scale ranging from 0 to 10, with bigher scores indicating greater levels of self-control. Using the scores reported by the survey respondents below, follow the steps all-les al significance of lwa intependently down simples to let the null typuhesis that brys and girls have the same mean level of self-exin. 10-05, iwo-lailed test: Show your work in ech sten) (pirls) Note: refer to the Slides 22-25 af the video for the steps and for a similar example Bous Self-Control Score (Xi) Girls Self-Control Score X-) 5) Caleulate the value 6) Determine the Talle Critical t value by using Table C. Appendix C ST 7) Compare the Calcululed value with the Table Critical valuc 1) State the Ho and H (expressed in hoth words und muchematical termi) 8) Draw your conclusion about the Null Hypothesis (llo) 2) Find the menn for unch group

Answer 1

(X-X - Boys Self cente Score (X1) self-control cove 0-49 2.89 0.09 ر و شد. در هرات 69 529 2.89 0:49 2.25 6.25 0.25 2.25 0.25 6.25 2:25 0.25 0.25 2.25 22.5 girls and boys. 1 0.09 021 Ho: Self control level are same in lx, luxa H, : Self control level in boys is less compared to girls ex <lxo (left-sided Hypothesis) 2 Mean of self control score of Boys (X) = 57/10 = 5.7 Mean of self control score of 6.5 Girls (72) = 65/10 37 Variance for (x) = {(x1 - x)² = 32.1 = 3.5666 02 Variance of Variance for (x2) = {(4- X 2)" = 22.5 = 2.5 n₂-1 41 Standard Enoo of the difference between means Tux-lx = x + x2 N ni 012- 3.5666. + 2. 5 10 0 .6066 - 04788 N

5 t-value t = x - 72 = 5.7-6.5 0.7788 ux, uxz - E-1-02722 6) Critical Value To find critical value look for (n,+ n2-2) dof ie 18 dif at x=0.05 (one-tail) teritical =-1-734 7 Iteal 1 <teri 3] We do not Reject Ho... -1.739 . We can conclude that means of self-control score do not differ. Rejection (Table will give you the probabilities of Right - tail) But Distribution is Symmetric. - Area above t = 1.734 is equal to Area below t = -1.734.