Question

(6 points) Cars on Campus. Statistics students at a community college wonder whether the cars belonging to students are, on average, older than the cars belonging to faculty. They select a random sample of 23 cars in the student parking lot and find the average age to be 8.5 year with a standard deviation of 5.3 year. A random sample of 23 cars in the faculty parking lot have an average age of 3.4 years with a standard deviation of 4.4 years. 1. The null hypothesis is Ho: Hs=uf. What is the alternate hypothesis? A HA s uf B. HA Ms uf C. HA: s u 2. Calculate the test statistic. ? 3. Calculate the p-value for this hypothesis test p value 4. Calculate the effect size for this hypothesis test. effect size 4. Suppose that students at a nearby university decide to replicate this test. They obtain samples from their university student and faculty lots and, using their new sample data, conduct the same hypothesis test They calculate a p-value of-0.0345 and an effect size of 0.819. Do their results confirm or conflict with the results at the community college? A It confirms the community college results because the p-value is much smaller. B. It can neither confirm or contradict the community college results because we don't know the sample sizes the university students used. C. It contradicts the community college results because the p-value is much bigger D. It confirms the community college results because the effect size is nearly the same. E. It contradicts the community college results because the effect size is much smaller

Answer 1

Ans:

1)

Option A is correct.

(right tailed test)

2)t statistic

Test statistic:

t=(8.5-3.4)/SQRT((5.3^2/23)+(4.4^2/23))

t=3.5507

3)

df=23+23-2=44

p-value=tdist(3.5507,44,1)=0.0005

4)effect size=(8.5-3.4)/SQRT(5.3^2+4.4^2)=0.74

5)

Option C is correct

it contradicts the community college results because p-value is much bigger.