Two independent groups of students were selected to participate in a study to determine if having video lectures in an online class has an effect on test scores. The students were randomly (SRS)...

Two independent groups of students were selected to participate in a study to determine if having video lectures in an online class has an effect on test scores. The students were randomly (SRS) placed into 2 groups, one group was the online class of 30 students with video lectures and the other group was the online class of 33 students without video lectures. The average test score on the online class of 30 students with video lectures was x-bar:  87 with a standard deviation of s = 1.8 and the average test score the online class of 33 students without video lectures x-bar = 86 with a standard deviation of s = 3.2. Is there enough evidence at the 1% level that the test scores of the online class with video lectures are higher than the test scores of the online class without video lectures? State the 99% confidence interval:

a) (87-86) – (0.99)(0.6468) = 0.3597 (87-86) + (0.99)(0.6468) = 1.64 We are 99% confident that the average test scores of the online class with video lectures are between 0.3597 points HIGHER to 1.64 points HIGHER than the average test scores of the online class without video lectures.

b) (87-86) – (0.99)(0.6468) = 0.3597 (87-86) + (0.99)(0.6468) = 1.64 We are 99% confident that the average test scores of the online class with video lectures are between 35.97% HIGHER to 1.64% HIGHER than the average test scores of the online class without video lectures.

c) (87-86) – (2.66)(0.6468) = -0.73 (87-86) + (2.66)(0.6468) = 2.73 We are 99% confident that the average test scores of the online class with video lectures are between 0.73 points LOWER to 2.73 points HIGHER than the average test scores of the online class without video lectures.

d) (87-86) – (2.66)(0.6468) = -0.73 (87-86) + (2.66)(0.6468) = 2.73 We are 99% confident that the average test scores of the online class with video lectures are between 73% LOWER to 2.73% HIGHER than the average test scores of the online class without video lectures.