1. A researcher
hypothesizes that individuals who listen to classical music will score
differently from the general population on a test of spatial ability. On a
standardized test of spatial ability, Âľ =58. A random sample of 14 individuals
who listen to classical music is given the same test.

Their scores on the
test are 52, 59, 63, 65, 58, 55, 62, 63, 53, 59, 57, 61, 60, 59.

a. Is this a one- or
two-tailed test?

b. What are H0 and Ha
for this study?

c. Compute tobt.

d. What is tcv?

e. Should H0 be
rejected? What should the researcher conclude?

f. Determine the 95%
confidence interval for the population mean, based on the sample

mean.

2. A researcher
believes that the percentage of people who exercise in California is greater
than the national exercise rate. The national rate is 20%. The researcher
gathers a random sample of 120 individuals who live in California and finds
that the number who exercise regularly is 31 out of 120.

a. What is obt?

b. What is df for this
test?

c. What is cv?

d. What conclusion
should be drawn from these results?

3. Researchers at a
food company are interested in how a new spaghetti sauce made from green
tomatoes (and green in color) will compare to their traditional red spaghetti
sauce. They are worried that the green color will adversely affect the
tastiness scores. They randomly assign subjects to either the green or red
sauce condition. Participants indicate the tastiness of the sauce on a 10-point
scale. Tastiness scores tend to be skewed. The scores follow.

Participant Red Sauce
Green Sauce

1 7 4

2 6 3

3 9 6

4 10 8

5 6 7

6 7 5

7 8 9

a. What statistical
test should be used to analyze these data?

b. Identify H0 and Ha
for this study.

c. Conduct the
appropriate analysis.

d. Should H0 be
rejected? What should the researcher conclude?

4. You notice in your
introductory psychology class that more women tend to sit up front, and more
men sit in the back. To determine whether this difference is significant, you
collect data on the seating preferences for the students in your class. The
data follow.

Men Women

Front of the Room 15
27

Back of the Room 32 19

a. What is X²
obt?

b. What is df for this
test?

c. What is X²cv?

d. What conclusion
should be drawn from these results?