You took independent random samples of 20 students at City College and 25 students at SF State. You asked each

student how many sodas they drank over the course of a year. The sample mean at City College was 80 and the

sample standard deviation was 10. At State the sample mean was 90 and the sample standard deviation was 15. Use

a subscript of c for City College

and a subscript of s for State.

1.

Calculate a point estimate of the difference between the two population means.

2.

Calculate the appropriate number of degrees of freedom to use for your analysis. Hint: Remember that you

always round

down

for degrees of freedom if you get a decimal answer.

Note: To calculate this answer you

must use the for

mula which assumes unequa

l varia

nces. This can be found on p. 578 of the textbook, or the

last page of the Section 11.2 Learn

Section on Hawkes, or on

page 2 of the Hypoth

esis Testing Summary

file.

3.

Determine a 95% confidence interval for the difference between the tw

o population means.

4.

Give the null and alternative hypotheses for a hypothesis test to test to see if there is a statistically significant

difference in the population means between students at the two schools.

5.

State using the confidence level in question 3.

6.

Calculate

the value of the test statistic.

7.

Find a range for the p

-

value.

8.

What is your conclusion in statistical terms?

9.

Explain the meaning of this conclusion in business terms.

10.

What

statistical

conclusion would you reach using the confidence

interval approach? Explain how you reach

this conclusion. Is it the same conclusion you reached using the p

-

value approach?