DATA ANALYSIS 17
Data are obtained from a random sample of adult women with
regard to their ages and their monthly expenditures on health
products. The resulting regression equation is:
Expenditure = 43 + 0.23(Age) with r = 0.27.
What percentage of the variation in expenditures can be
explained by looking at the ages?
A. 0.23%
B. 23%
C. 7.29%
D. 27%
E. 52%
DATA ANALYSIS 18
Given these parallel boxplots, which of the following are true?
(choices on next slide)
I. The ranges are the same.
II. The interquartile ranges are the same.
III. Both sets are skewed to both lower and higher values.
A. I only
B. II only
E. I, II, and III
C. III only
D. I and II
DATA ANALYSIS 19
Suppose the average score on a national exam is 500 with a
standard deviation of 100. If each score is increased by 20 and the
result is increased by 10%, what are the new mean and standard
deviation?
A.
µ = 570, σ = 100
B.
µ = 570, σ = 110
C.
µ = 572, σ = 100
D.
µ = 572, σ = 110
E.
µ = 572, σ = 132
DATA ANALYSIS 20
Which of the following statements about residuals are true?
I. The mean of the residuals is always zero.
II. The regression line for a residual plot is a horizontal line.
III. The standard deviation of the residuals gives a measure of
how the points in the scatterplot are spread around the
regression line.
A. I and II
B. I and III
C. II and III
D. I, II, and III
E. None of the above gives the complete set of true responses.
DATA ANALYSIS 21
Consider the following picture of revenue over 3 years.
Which of the statements on the following slide are true?
I. Revenue dropped approximately in half from 2004-2005
and then approximately in half again from 2005-2006.
II. The choice of labeling makes for a misleading revenue
picture.
III. The above picture is not a histogram.
A. I only
B. II only
C. III only
D. II and III
E. None of the above gives the complete set of true
responses.
DATA ANALYSIS 22
If every man married a woman who was exactly 3 years
younger than he, what would be the correlation between the
ages of married men and women?
A. Somewhat negative
C. Somewhat positive
B. 0
D. Nearly 1
E. 1
DATA ANALYSIS 23
In which of the following histograms is the mean less than the
median?
DATA ANALYSIS 24
A teacher is teaching two AP Statistics classes. On the final
exam, the 25 students in the first class averaged 87, while the
30 students in the second class averaged 98. If the teacher
combines the classes, what will the average final exam score
be?
A. 92
B. 92.5
C. 93
D. 94.5
E. 95
DATA ANALYSIS 25
Which of the following statements are true?
I. Both dotplots and stemplots can show symmetry, gaps, clusters,
and outliers.
II. In histograms, relative areas correspond to relative frequencies.
III. In histograms, frequencies can be determined from relative
heights.
A. II only
B. I and II
E. I, II, and III
C. I and III
D. II and III
DATA ANALYSIS 26
The number of students taking AP Statistics at a high school during
the years 2000-2007 is fitted with a least squares regression line.
The graph of the residuals and some computer output is as follows:
Dependent variable is: Students
s = 9.758
R-sq = 93.4%
R-sq (adj) = 92.4%
Variable
Constant
Years
Coeff
11
13.9286
s.e.
6.299
1.506
t
1.75
9.25
How many students took AP Statistics in the year 2003?
A. 47
B. 48
C. 52
D. 53
p
0.1313
0.0001
E. 58
DATA ANALYSIS 27
Suppose the regression line for a set of data, ŷ = a + 4x, passes
through the point (1,3). If x and ȳ are the sample means of
the x- and y-values, respectively, then ȳ =
A. X
B. 4x
C. 3 + 4x
D. 2 + x
E. -1 + 4x
DATA ANALYSIS 28
Consider the scatterplot of midterm and final exam scores for
a class of 20 students. Which of the following statements on
the next slide is true?
I. The same number of students scored 100 on the midterm
as did on the final.
II. The same percentage of students scored below 50 on
each exam.
III. Students who scored higher on the midterm tended to
score higher on the final.
A. I and II
B. I and III
C. II and III
D. I, II, and III
E. None of the above gives the complete set of true
responses.
DATA ANALYSIS 29
If the standard deviation of a set of observations is 0, you can
conclude:
A.
B.
C.
D.
E.
That there is no relationship between the observations.
That the average value is 0.
That all observations are the same value.
That a mistake in arithmetic has been made.
None of the above.
DATA ANALYSIS 30
Which of the following statements about the correlation r are
true?
I. The correlation and the slope of the regression line always have
the same sign.
II. A correlation of -0.32 and a correlation of +0.32 show the same
degree of clustering around the regression line.
III. A correlation of 0.78 indicates a relationship that is 3 times as
linear as one for which the correlation is 0.26.
A. I and II
B. I and III
C. II and III D. I, II, and III
E. None of the above gives the complete set of true responses.
DATA ANALYSIS 31
These dotplots for randomly selected male and female
students at a particular high school show the number of times
per week they eat at fast food restaurants.
Which of statements on the following slide are true?
I. One distribution is roughly symmetric; the other is skewed
left.
II. The difference in their means is less than the difference in
their medians.
III. The ranges are the same.
A. I and II
B. I and III
C. II and III D. I, II, and III
E. None of the above gives the complete set of true
responses.
DATA ANALYSIS 32
Suppose the correlation between two variables is r = 0.28.
What will the new correlation be if 0.17 is added to all value of
the x-variable, every value of the y-variable is doubled, and the
two variables are interchanged?
A. 0.28
B. 0.45
C. 0.56
D. 0.90
E. -0.28