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DATA ANALYSIS 53
Given the two histograms below, which of the following
statements are true?
I. The Empirical Rule applies only to set A.
II. You can be sure that the standard deviation of set A is
greater than 5.
III. You can be sure that the standard deviation of set B is
greater than 5.
A. I only
B. II only
C. I and II
D. I and III
E. II and III
DATA ANALYSIS 54
A data set includes two outliers, one at each end. If both these
outliers are removed, which of the following is a possible result?
A. Both the mean and standard deviation remain unchanged.
B. Both the median and standard deviation remain unchanged.
C. Both the standard deviation and variance remain
unchanged.
D. Both the mean and median remain unchanged.
E. Both the mean and standard deviation increase.
DATA ANALYSIS 55
The following is a histogram of test scores. Which of the
statements on the following slide are true?
I. The median score was 75.
II. If 90 and above was an A, most students received an
A.
III. More students scored below 70 than above 90.
A. I only B. II only
E. None are true.
C. III only
D. All are true.
DATA ANALYSIS 56
A linear regression analysis is performed on the data from two
scatterplots, A and B, resulting in identical least squares
regression lines with positive slopes.
Which of the statements on the following slide is true?
A. The sum of the squares of the residuals in A equals the sum
of the squares of the residuals in B.
B. The correlation in A equals the correlation in B.
C. If the sum of the squares of the residuals in A is greater
than the sum of the squares of the residuals in B, than the
correlation in A will be greater than the correlation in B.
D. If the sum of the squares of the residuals in A is greater
than the sum of the squares of the residuals B, then the
correlation in A will be less than the correlation in B.
E. None of the above are true statements.
DATA ANALYSIS 57
Consider n pairs of numbers. Suppose x-bar = 4, sx = 3,
y-bar = 2, and sy = 5.
Of the following which could be the least squares line?
A.
B.
C.
D.
E.
y=2+x
y = -6 +2x
y = -10 + 3x
y = 5/3 – x
y=6-x
DATA ANALYSIS 58
A histogram of the educational level (in number of years of
schooling) of the adult populations of the United States
would have which of the following characteristics?
I. Symmetry
II. Clusters
III. Skewness to the left
A. II only
D. II and III
B. I and II
E. I, II, and III
C. I and III
DATA ANALYSIS 59
A doctor wishes to compare the resting heart rates of his
younger patients (younger than 30 years old) versis his older
patients (older than 30 years old). Which of the following
graphical displays is inappropriate?
A.
B.
C.
D.
E.
back-to-back stemplot
Parallel boxplots
Side by side histograms
Scatterplot
All the above displays are inappropriate.
DATA ANALYSIS 60
Which of the following are true statements about the correlation
coefficient r ?
I.
It is not affected by changes in the measurement units of the
variables.
II. It is not affected by which variable is called x and which is
called y.
III. It is not affected by extreme values.
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 61
Which of the following measures are most usually given to
describe the center and spread of a distribution as given in the
dotplot?
A.
B.
C.
D.
E.
Mean and standard deviation
Mean and interquartile range
Mean and range
Median and interquartile range
Median and range
DATA ANALYSIS 62
Suppose the correlation between two variables is 0.85.
If each of the y-values is multiplied by -1, which of the
following is true about the new scatterplot?
A.
B.
C.
D.
E.
It slopes up to the right, and the correlation is -0.85.
It slopes down to the right, and the correlation is -0.85.
It slopes up to the right, and the correlation is 0.85.
It slopes down to the right, and the correlation is 0.85.
None of the above is true.
DATA ANALYSIS 63
Which of the following distributions has a mean of 60 and a
standard deviation of 4 ?
DATA ANALYSIS 64
Suppose X and Y are random variables with µᵪ= 38, σᵪ= 12,
µᵧ= 35, and σᵧ= 9.
Given that X and Y are independent, what is the standard
deviation of the random variable X-Y ?
A. √3
B. √21
C. 3
D. 15
E. 21
DATA ANALYSIS 65
Which of the following statements are true?
I. All symmetric histograms have single peaks.
II. All symmetric bell-shaped curves are normal.
III. All normal curves are bell-shaped and symmetric.
A. I only B. II only C. III only D. I and II
E. None of the above gives the complete set of true responses.
DATA ANALYSIS 66
Below is a scatterplot with one point labeled X.
Suppose you find the least squares regression line.
Which of the statements on the following slide are true?
I.
X has the largest residual, in absolute value, of any point
on the scatterplot.
II. X is an influential point.
III. The residual plot will show a curved pattern.
A. I only
E. II and III
B. II only
C. III only
D. I and III
DATA ANALYSIS 67
Data on the number of cancer deaths among Americans (in 1,000s) and
years (since 2001) result in the regression line: Deaths= 550 – 6.05(years)
with r = 0.863. What is the correct interpretation of the slope?
A. The number of cancer deaths among Americans has been dropping by
an average of 6,050 per year since 2001.
B. The baseline number of cancer deaths among Americans is 550,000.
C. The regression line explains 74.5% of the variation in cancer deaths
among Americans over the years since 2001.
D. The regression line explains 86.3% of the variation in cancer deaths
among
Americans over the years since 2001.
E. Cancer will be cured in the year 2092.