Question

Two statistics classes were asked if A Christmas Story is the best holiday movie. In the first class, 30 out of 40 students answered correctly and said that it was. In the second class, 45 out of 50 students answered correctly and said that it was. Is there a statistical difference in the two classes at the .05 level of significance? What about at the .01 level?

Answer 1

There is significant difference between the proportions

Explanation:

Given that the two statistics classes were asked if A Christmas Story is the best holiday movie.

Class I II Total

n 40 50 90

x 30 45 75

p=x/n 0.75 0.90 0.8333

H0: p1 =p2

H0: p1 ≠p2

(Two tailed test at 5% level)

p difference = -0.15

STd error for difference =
`√(pq/n) =√(0.8333*0.1667/90) \\=0.03727`

Z statistic = p difference/std error

=-4.0246

p <0.00001

Since p <0.05 we reject H0. There is significant difference between the proportions

At 0.01 level also p is less than alpha So same conclusion