Sample 1 - Faculty

8.1 Exercise #25 

The mean ACT score for 43 male high school students is 21.1 and the standard deviation is 5.0. The mean ACT score for 56 female high school students is 20.9 and the standard deviation is 4.7. At   0 . 01 , can you reject the claim that male and female high school students have equal ACT scores?

8.1 Stuff 

Two samples are independent if the sample selected from one population is not related to the sample selected from the second population.



Two samples are dependent if each member of one sample corresponds to a member of the other sample. Dependent samples are also called paired samples or matched samples.

8.1 Exercises 

Sample 1: The IQ scores of 60 females. Sample 2: The IQ scores of 60 males.



Sample 1: The SAT scores of 44 high school students. Sample 2: The SAT scores of the same 44 high school students after taking an SAT prep course.

8.1 Exercise #25 

The mean ACT score for 43 male high school students is 21.1 and the standard deviation is 5.0. The mean ACT score for 56 female high school students is 20.9 and the standard deviation is 4.7. At   0 . 01 , can you reject the claim that male and female high school students have equal ACT scores?

8.1 Stuff 1) The samples must be randomly selected.

2) The samples must be independent. 3) Each sample size must be at least 30 or, if not, each population must have a normal distribution with a known standard deviation.

8.1 Stuff 

The sampling distribution for x1  x 2 is a normal distribution with mean and standard deviation of x

1

x2

  x1   x 2   1   2

and x

1

x2



x x 2

1

2 2



1

2

n1



2 n2

2

8.1 Exercise #25



There is insufficient evidence at the 1% level to reject the claim that male and female high school students have equal ACT scores.