Question

A professor in the psychology dept at State U. would like to determine whether more students have low grades in Statistics courses than in other courses in the dept. It is known that the overall grade distribution for the dept is 15% As, 25% Bs, 30% Cs, 20% Ds, and 10% Fs. A sample of 100 students taking statistics last year produced the following grade distribution for statistics grades (observed frequencies):     

1. What specific statistical procedure would you use to test whether the distribution of grades in statistics (observed frequencies) is consistent with the distribution of grades for psychology courses overall (expected frequencies)?  

A	B	C	D	F
20	35	30	12	3

2. Create the expected frequency table. (1 point)

A	B	C	D	F

3. Based on the data in these tables, do you think that this professor is correct – that the distribution of statistics grades show more lower grades than grades in the psychology dept. overall?     
4. Why or why not? (You don’t need to do the analysis to answer this question correctly.)   

Answer 1

the critical value of chi-squre at 0.05 level of significance and df=4 is =9.4877.since test statistic value is greater than critical value we reject the null hypothesis.so the professor is not correct