Question

Direction: A small data set is given below. You will run a t-test using Excel. You must provide Excel output to get full credit for this question. A medical researcher wants to determine whether a drug changes the body’s temperature. Seven test subjects are randomly selected, and the body temperature (in degrees Fahrenheit) of each is measured. The subjects are then given the drug and after 20 minutes, the body temperature of each is measured again. The results are listed below. Use significance level α = 0.05, and we assume that the body temperatures are normally distributed.

Subject 1 2 3 4 5 6 7

Initial Temperature 101.8 98.5 98.1 99.4 98.9 100.2 97.9

Second Temperature 99.2 98.4 98.2 99.0 98.6 99.7 97.8

Provide results for the following questions: 1. Which t-test you used? 2. Degrees of freedom? 3. t-statistic of the test? 4. One or two tailed hypothesis testing used? 5. p value? 6. Do you reject or fail to reject the null hypothesis? 7. At α = 0.05, is there enough evidence to conclude that the drug changes the body’s temperature? (you will make an inference about results)

Answer 1

By using excel we have to solve this question.

1) Here we have given before and after type data so we have to use pair t-test.

2) Degrees of freedom = n - 1 = 7 - 1 = 6

Claim: A drug changes the body’s temperature.

The null and alternative hypothesis is

First, enter data into excel, then click on Data -------> Data Analysis -------->t-Test: Paired Two Samples For Means --------->Variable 1 Range: Select Initial temperature data -------->

Variable 2 Ragne: Select second temperature data -----> Hypothesized Mean difference: 0

Alpha: 0.05 --------> Output: Select any empty cell ---------->ok

We get

3) The test statistic is t = 1.60

4) Our hypothesis is a two-tailed test because the alternative hypothesis has not equal sign.

5) P-value = 0.1616

6) P-value > 0.05 we fail to reject null hypothesis.

7) Conclusion: There is not enough evidence to conclude that the drug changes the body’s temperature.