A psychologist Is examining the influence of an older siblin

A psychologist Is examining the influence of an older sibling in the development of Adults Is obtained. Half of these people had no siblings and the others had at least one who Is within S years his or her age. The psychologist records a aggression level for each participant a obtained the following data: Do these data indicate that having a sibling has a significant effect on the development of aggression? Use a two-tailed test at the .05 level.

Solution

Ho:there is no significant effect on the development of aggression basing on siblings. H1:there is a significant effect on the development of aggression basing on siblings. Given n1=n2=12, xbar=17,ybar=24, ss(x)=580 & ss(y)=608. Then tcal=|xbar-ybar|/((S²[(1/n1)+(1/n2)]) where S²=(1/(n1+n2-2))*(ss(x)+ss(y))=(580+608)/22=1188/22=54, t=|17-24|/(54*.01667)=7/3=2.333 & t table value of 22 degrees of freedom at 0.05 is 2.07. So tcal>ttab, so we reject Ho, i.e., H1 is accepted. Therefore, there is a significant effect on the development of aggression basing on siblings.