Question

A teacher is trying to assign grades so that she has the following distribution: Grade %...

A teacher is trying to assign grades so that she has the following distribution:

Grade % of Class
A 15
B 30
C 40
D 10
F 5

This is what she actually has in her grade book:

Grade # Students
A 20
B 40
C 35
D 8
E 8

At a significance level of 0.05, are these two distributions different? Include either χ^2 or the p-value to justify your answer.

Math   Statistics-And-Probability   
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Homework Answers

Answer #1

Pearson chi square : Observed and Expected Counts

Category

Observed

Test
Proportion

Expected

Contribution
to Chi-Square

A

20

0.15

16.65

0.67402

B

40

0.30

33.30

1.34805

C

35

0.40

44.40

1.99009

D

8

0.10

11.10

0.86577

E

8

0.05

5.55

1.08153

We compute chi square value as 5.95946 and associated p value .202.

Since the p value is more than the nominal .05, evidence is not enough to conclude that the two distributions are significantly different.

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