benchiefjr said:

I have a question

Teaching method A produces a mean score of 75 on a standard test. Teaching method B has been introduced, and the first sample of 19 students achieved a mean score of 79 with a standard deviation of 8. At 5% level of significance, test the claim that method B is better.

H0 : Mb <= Ma

H1 : Mb > Ma

I completely forgot how to do this type. I have a feeling if i see it done, I'll remember. Please help me!

Teaching method A produces a mean score of 75 on a standard test. Teaching method B has been introduced, and the first sample of 19 students achieved a mean score of 79 with a standard deviation of 8. At 5% level of significance, test the claim that method B is better.

H0 : Mb <= Ma

H1 : Mb > Ma

I completely forgot how to do this type. I have a feeling if i see it done, I'll remember. Please help me!

X bar = 75

n = 19

std. dev. = 8

8/rad.19 = 1.835

75-8/1.835 = 36.5 which is > 1.835

Fail to reject H0. There is a significant difference between the two means, therefore supporting the claim that method B is better than method A.

Is this right?

benchiefjr said:

Like this one :

An experiment is devised to study the variability of grading procedures among college professors. Two different professors are asked to grade the same set of 25 exam solutions and their grades have variances of 103.4 and 39.7, respectively. At the 0.05 siginificance level, test the claim that the professor's grading exhibits greater variance.

H0 : o1 <= o2

H1 : o1 > o2

The o is like the std. dev. symbol i believe. I just can't tell if this is the same as the other problem because it has to do with variances.

An experiment is devised to study the variability of grading procedures among college professors. Two different professors are asked to grade the same set of 25 exam solutions and their grades have variances of 103.4 and 39.7, respectively. At the 0.05 siginificance level, test the claim that the professor's grading exhibits greater variance.

H0 : o1 <= o2

H1 : o1 > o2

The o is like the std. dev. symbol i believe. I just can't tell if this is the same as the other problem because it has to do with variances.

C.V. = 36.42

(24)(103.4)/39.7 = 62.5

62.5 > 36.42

Reject H0. The sample of 25 solutions comes from a distribution with a variance greater than 36.42.

Are these right, if not..please help! Also, if someone could do one of the other two, that'd be great because then i'd be finished.