A student is interested in whether students who study with o

A student is interested in whether students who study with others devote as much attention to their studies as do students who study alone. He believes those who study alone devote more attention to their studies. He randomly assigns participants to either group or individual study conditions and has them read and study the same passage of information for the same amount of time. Participants are then given the same 10-item test on the material. Their scores appear below. Scores on the test represent interval/ratio data and are normally distributed. Group Alone 6 10 5 9 6 7 5 7 6 6 6 6 7 8 8 6 5 9 a) What statistical test should be used to analyze these data? b) Identify H0 and Ha for this study. c) Conduct the appropriate analysis. d) Should H0 be rejected? What should the researcher conclude? e) If significant, compute the effect size and interpret this.

Solution

a) t test for to samples is used

b) H0: the mean marks in both the groups is same

H1: the mean marks in group study students < mean marks of students who study alone.

c) excel is used for the analysis.

t=-2.58

d) since p value is less than 0.05, hence we reject the null hypothesis. and conclude that the mean marks in group study students < mean marks of students who study alone.

e) effect size d=mod(xabr1-xbar2)/sqrt(var1+var2)/2=1.2181

this is a large effect size.