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STATISTICS The following gives the grade of students who took STAT and OR course

ID: 3176846 • Letter: S

Question

STATISTICS

The following gives the grade of students who took STAT and OR course simulateneously. Test the hypothesis at the 1% level that there is no difference in grading between the courses.

STATS GRADE...................OR GRADE

..........................A...................B......................C..................OTHER

A........................25..................6......................17.....................13

B.......................17..................16...................15........................6

C......................18....................4.....................18........................10

OTHER............10.......................8.....................11......................20

Explanation / Answer

from above appying chi distribution

for above degree of freedom =(row-1)(column-1) =(4-1)(4-1)=9

for 9 degree of freedom and chi stat 25.555, p value =0.0024

as p value is significantly low, we reject that there is no defference, and conclude that at least one subject has differnece.

Observed O A B C Other Total A 25 6 17 13 61 B 17 16 15 6 54 C 18 4 18 10 50 Other 10 8 11 20 49 Total 70 34 61 49 214 Expected E=rowtotal*column total/grand total A B C Other Total A 19.953 9.692 17.388 13.967 61 B 17.664 8.579 15.393 12.364 54 C 16.355 7.944 14.252 11.449 50 Other 16.028 7.785 13.967 11.220 49 Total 70 34 61 49 214 chi square =(O-E)^2/E A B C Other Total A 1.276 1.406 0.009 0.067 2.758 B 0.025 6.418 0.010 3.276 9.729 C 0.165 1.958 0.985 0.183 3.292 Other 2.267 0.006 0.630 6.871 9.775 Total 3.734 9.788 1.634 10.398 25.555