The Study

We obtained the list of the 100 students we surveyed at North Olmsted High School by computer randomization. Our population of interest is all of NOHS, and we used a sample size of 100 students to extrapolate to the population. Our sample includes random students from grades 9-12. We used Minitab to generate the sample of students from the list of the high school’s entire population. The type of test we ran was a 2 sample mean t-test, and this was chosen because we weren’t dealing with a population, therefore could not use a z-test. Also, we were comparing the means of two seperate variables so we used a 2 sample mean t-test.

The Survey:

What is your current cumulative GPA?

What is your natural hair color? check one of the below options.

__ Blond __Brown __Black __Red

Hypothesis Test:

U1=the true mean GPA of naturally blond students at North Olmsted High School

U2=the true mean GPA of students at North Olmsted High school who do not have naturally blond hair

Ho: U1-U2=0

Ha: U1-U2<0

a= 0.05

Assumptions:

Samples are independent and random.

The population is normally distributed.

t=1.86

p-value=0.960

Minitab Output:

Two-Sample T-Test and CI: Blond, Not Blond

Two-sample T for Blond vs Not Blond

N Mean StDev SE Mean

Blond 10 3.400 0.540 0.17

Not Blond 49 3.014 0.829 0.12

Difference = mu (Blond) - mu (Not Blond)

Estimate for difference: 0.386

95% upper bound for difference: 0.746

T-Test of difference = 0 (vs <): T-Value = 1.86 P-Value = 0.960 DF = 18