10.
A polling agency conducted a survey of 100 doctors on the question “Are you willing to treat
women patients with the recently approved pill RU-486”? The conservative margin of error
associated with the 95% confidence interval for the percent who say 'yes' is
a. 50%
b. 10%
c. 5% d. 2%
11.
Which one of these statistics is unaffected by outliers?
a.
Mean
b.
Interquartile range
c.
Standard deviation
d.
Range
12.
A list of 5 pulse rates is: 70, 64, 80, 74, 92. What is the median for this list?
a.
74
b. 76 c. 77 d. 80
13.
Which of the following would indicate that a dataset is not bell-shaped?
a.
The range is equal to 5 standard deviations.
b.
The range is larger than the interquartile range.
c.
The mean is much smaller than the median.
d.
There are no outliers.
14.
A scatter plot of number of teachers and number of people with college degrees for cities in
California reveals a positive association. The most likely explanation for this positive
association is:
a.
Teachers encourage people to get college degrees, so an increase in the number of
teachers is causing an increase in the number of people with college degrees.
b.
Larger cities tend to have both more teachers and more people with college degrees, so
the association is explained by a third variable, the size of the city.
c.
Teaching is a common profession for people with college degrees, so an increase in the
number of people with college degrees causes an increase in the number of teachers.
d.
Cities with higher incomes tend to have more teachers and more people going to college,
so income is a confounding variable, making causation between number of teachers and
number of people with college degrees difficult to prove.
15.
The value of a correlation is reported by a researcher to be
r
=
−
0.5. Which of the following
statements is correct?
a.
The x-variable explains 25% of the variability in the y-variable.
b.
The x-variable explains
−
25% of the variability in the
y
-variable.
c.
The x-variable explains 50% of the variability in the
y
-variable.
d.
The x-variable explains
−
50% of the variability in the
y
-variable.
16.
What is the effect of an outlier on the value of a correlation coefficient?
a.
An outlier will always decrease a correlation coefficient.
b.
An outlier will always increase a correlation coefficient.
c.
An outlier might either decrease or increase a correlation coefficient, depending on
where it is in relation to the other points.
d.
An outlier will have no effect on a correlation coefficient.