Question

4. I have reviewed the midterm grades, and I am trying to predict how well the class will do on the final exam. The frequency values are actual grades for the Summer II midterm:
Grade	Expected	Frequency (Observed)
Greater than A	5	7
A	6	9
B	8	4
C	3	4
D	1	0
F	2	1

a. What will be my degrees of freedom?

b. What is O-E (difference) for grades of B?

c. What is O-E^2 for grades of A?

d. What is (O-E)^2/E for grades of F?

e. What is O-E (difference) for grades of B?

f. What is the chi square (χ2) test statistic?

g. What is the p-value?

h. At the 5% significance level, what is your decision?

i. What is the reason for the decision?

j. What is the conclusion in full sentences?

Answer 1

>A	5	0.2
A	6	0.24
B	8	0.32
C	3	0.12
D	1	0.04
F	2	0.08
Total	25

Categories	Observed	Expected	(fo-fe)2/fe
>A	7	25*0.2=5	(7-5)2/5 = 0.8
A	9	25*0.24=6	(9-6)2/6 = 1.5
B	4	25*0.32=8	(4-8)2/8 = 2
C	4	25*0.12=3	(4-3)2/3 = 0.333
D	0	25*0.04=1	(0-1)2/1 = 1
F	1	25*0.08=2	(1-2)2/2 = 0.5
Sum =	25	25	6.133