WEB CALCULATOR EXERCISE 3
Web Calculator Exercise 3
T test for independent groups and dependent groups (Twogroup designs)
1. An LU professor is interested in whether there is a difference between undergraduate students and graduate students in the amount of time spent praying each day. The professor gathers information from random samples of undergraduate and graduate students on the LU campus. The amount of time praying is normally distributed and is measured on an interval/ratio scale.
Graduate 
Undergraduate 
15 
9 
17 
11 
10 
9 
13 
6 
11 
5 
17 
6 
a. What statistical test should be used to analyze the data?
b. Is this a one or two tailed test?
c. Identify H_{0} and H_{a} for this study.
d. Conduct the appropriate analysis. Should H_{0} be rejected?
2. A teacher wants to investigate whether there is a difference between male and female students in the amount of time they spend studying for statistics. The table below shows the amount of time students spend studying statistics each week. The amounts of time spent studying are normally distributed.
Male 
Female 
27 
25 
25 
29 
19 
18 
10 
23 
16 
20 
17 
15 
15 
19 
a. What statistical test should be used to analyze the data?
b. Is this a one or two tailed test?
c. Identify H_{0} and H_{a} for this study.
d. Conduct the appropriate analysis. Should H_{0} be rejected?
3. A researcher is interested in whether listening to music helps or hinders testperformance. To control for differences in cognitive level, this researcher decides to use a withinparticipants design. He selects a random sample of participants and has them study different material of equal difficulty in both the music and no music conditions. Participants take a 20item quiz on the material. The table below shows the scores on the quiz. The study is completely counterbalanced to control for order effects. The scores obtained are measured on an intervalratio scale and are normally distributed.
Music 
No Music 
17 
17 
16 
18 
15 
17 
16 
17 
18 
19 
18 
18 
a. What statistical test should be used to analyze the data?
b. Is this a one or two tailed test?
c. Identify H_{0} and H_{a} for this study.
d. Conduct the appropriate analysis. Should H_{0} be rejected? What should the researcher conclude?
e. Calculate the 95 confidence interval.
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WEB CALCULATOR EXERCISE 3