4. Explain what each of the following sample correlation
coefficients tells you about the relationship between the x and y
values in the sample.
5. Construct a scttergram for each data set. Then calculate r and
r 2 for each data set. Interpret their values. Complete parts a through d.
6. A university conducted a study on 446 business graduates who
had all completed the same business course. The study used
correlation coefficients to investigate the relationship between many
different business skills. Two of the many variables measured were
self-knowledge skill level (x) and goalsetting ability (y). The
correlation was r = 0.82. Complete parts a through c below.
7. Studies of managers from two countries in the 1970s found
differences of opinion toward quality management. To find out if
these differences continue to exist, researchers surveyed 100
managers in each country in the electronics manufacturing industry.
The accompanying table gives the percentages of managers from each
country who agree with each of 10 randomly selected statements
regarding quality. Complete parts a through c.
8. Suppose a statistication built a multiple regression model for
predicting the total number of runs scored by a baseball team during a
season.Use the β estimates to predict the number of runs scored by a
team with 303 walks, 856 singles, 263 doubles, 37 triples, and 124
home runs.
9. Consider fitting the multiple regression model, E(y), below. A
matrix of correlations for all pairs of independent variables on the
right. Do you detect a multicollinearity problem?
10. Identify the problem(s) in the residual plots shown below.
11. Researchers conducted a survey of a representative sample of
over 1,000 drivers. Based on how often each driver engaged in road
rage behaviour, a road rage score was given. The driver were also
grouped by animal income. The data were subjected to an analysis of
variance, with the results summarized in the table.
12. What conditions must n satisfy to make the x 2 test valid?