Writing practice problems Homework

Chapter 7

15. In a particular country, it is known that college seniors report falling in love an

average of 2.20 times during their college years. A sample of five seniors, originally

from that country but who have spent their entire college career in the

United States, were asked how many times they had fallen in love during their

college years. Their numbers were 2, 3, 5, 5, and 2. Using the .05 significance

level, do students like these who go to college in the United States fall in love

more often than those from their country who go to college in their own country?

(a) Use the steps of hypothesis testing. (b) Sketch the distributions involved.

(c) Explain your answer to someone who is familiar with the Z test

(from Chapter 5) but is unfamiliar with the t test for a single sample.

Chapter 8

18. Twenty students randomly assigned to an experimental group receive an

instructional program; 30 in a control group do not. After 6 months, both groups

are tested on their knowledge. The experimental group has a mean of 38 on the

test (with an estimated population standard deviation of 3); the control group

has a mean of 35 (with an estimated population standard deviation of 5). Using

the .05 level, what should the experimenter conclude? (a) Use the steps of

hypothesis testing, (b) sketch the distributions involved, and (c) explain your

answer to someone who is familiar with the t test for a single sample but not

with the t test for independent means.

Chapter 9

18. A psychologist studying artistic preference randomly assigns a group of 45 participants

to one of three conditions in which they view a series of unfamiliar abstract

paintings. The 15 participants in the Famous condition are led to believe that

these are each famous paintings; their mean rating for liking the paintings is 6.5

(S = 3.5). The 15 in the Critically Acclaimed condition are led to believe that

these are paintings that are not famous but are very highly thought of by a group

of professional art critics; their mean rating is 8.5 (S = 4.2 ). The 15 in the Control

condition are given no special information about the paintings; their mean rating

is 3.1 (S = 2.9 ). Does what people are told about paintings make a difference

in how well they are liked? Use the .05 level. (a) Use the steps of hypothesis testing; (c) figure the effect size for the study; (d) explain your answer to part (a) to someone who is familiar with the t test for independent means but is unfamiliar with analysis of variance

Chapter 11

11. Make up a scatter diagram with 10 dots for each of the following situations:

(a) perfect positive linear correlation, (b) large but not perfect positive linear

correlation, (c) small positive linear correlation, (d) large but not perfect negative

linear correlation, (e) no correlation, (f) clear curvilinear correlation.

13. Four young children were monitored closely over a period of several weeks to

measure how much they watched violent television programs and their amount

of violent behavior toward their playmates. The results were as follows:

(a) Make a scatter diagram of the scores; (b) describe in words the general pattern of correlation, if any; (c) figure the correlation coefficient; (d) figure whether the correlation is statistically significant

(use the .05 significance level, two-tailed); (e) explain the logic of what

you have done, writing as if you are speaking to someone who has never heard

of correlation (but who does understand the mean, deviation scores, and hypothesis

testing); and (f) give three logically possible directions of causality, indicating

for each direction whether it is a reasonable explanation for the correlation

in light of the variables involved (and why).

Can anyone help me?