Transcript File - AP Statistics

DATA ANALYSIS 33
The amount of Omega 3 fish oil in capsules labeled 1,000 mg
is measured for four manufacturers’ products yielding the
following box plots.
Which of the manufacturers samples have the smallest range?
A.
B.
C.
D.
E.
A
B
C
D
There is insufficient information to answer this question.
DATA ANALYSIS 34
A random sample of golf scores gives the following summary
statistics:
n = 20, x = 84.5, Sx = 11.5, minX = 68, Q1 = 78,
Med = 86, Q3 = 91, maxX = 112.
What can be said about the number of outliers?
A. 0
B. 1
E. At least 2
C. 2
D. At least 1
DATA ANALYSIS 35
Which of the following statements are true?
I. Two students working with the same set of data may come up
with histograms that look different.
II. Displaying outliers is less problematic when using histograms
than when using stemplots.
III. Histograms are more widely used than stemplots or dotplots
because histograms display the values of individual
observations.
A. I only
B. II only
C. III only
D. I and II
E. II and III
DATA ANALYSIS 36
Consider the following three scatter plots.
Which has the greatest correlation coefficient r ?
A. I
B. II
C. III
D. They all the same correlation coefficient
E. The question cannot be answered without additional
information.
DATA ANALYSIS 37
A simple random sample of 25 world-ranked tennis players provides the
following statistics:
number of hours of practice per day x-bar = 7.3, sx = 1.2,
yearly winnings y-bar = $1,820,000, sy = $310,000, Correlation r = 0.23.
Based on this data, what is the resulting linear regression equation?
A.
B.
C.
D.
E.
Winnings = 1,390,000 + 59,400 hours
Winnings = 1,300,000 + 71,300 hours
Winnings = -63,400 + 258,000 hours
Winnings = -443,000 + 310,000 hours
Winnings = -10,000,000 + 1,620,000 hours
DATA ANALYSIS 38
Given this back-to-back stemplot, which of the statements on the
following slide are true?
I. The distributions have the same mean.
II. The distributions have the same range.
III. The distributions have the same variance.
A. II only
D. II and III
B. I and II
E. I, II, and III
C. I and III
DATA ANALYSIS 39
Using the most commonly accepted definition of outliers, a set
has five outliers. If every value of the set is increased by 20%,
how many outliers will there now be?
A. Fewer than 5
B. 5
C. 6
D. More than 6
E. It is impossible to determine without further information.
DATA ANALYSIS 40
Which of the following statements about the correlation r are
true?
I. When r = 0, there is no relationship between the variables.
II. When r = 0.2, 20% of the variables are closely related.
III. When r = 1, there is a perfect cause-and-effect relationship
between the variables.
A. I only B. II only C. III only
E. All the statements are false.
D. I, II, and III
DATA ANALYSIS 41
Given the histogram below, and using the most commonly
accepted definition of outliers, what values would be
considered outliers? (Answers on next slide)
A.
B.
C.
D.
E.
Between 115 and 120
Between 110 and 120.
Between 50 and 55, or between 115 and 120.
Between 50 and 55, or between 110 and 120.
There are no outliers.
DATA ANALYSIS 42
Suppose a study finds that the correlation coefficient relating
job satisfaction to salary is r = +1.
Which of the following are proper conclusions?
I. High salary causes high job satisfaction.
II. Low salary causes low job satisfaction.
III. There is a very strong association between salary and job
satisfaction.
A. I only
B. II only
C. III only
D. I and II
E. I, II, and III
DATA ANALYSIS 43
To which of the following histograms can the boxplot
correspond?
DATA ANALYSIS 44
When a set of data has suspect outliers, which of the
following are preferred measures of central tendency and of
variability?
A.
B.
C.
D.
E.
Mean and standard deviation
Mean and variance
Mean and range
Median and range
Median and interquartile range
DATA ANALYSIS 45
Which of the following statements are true?
I. The range of the sample data set can never be greater
than the range of the population.
II. While the range is affected by outliers, the interquartile
range is not.
III. Changing the order from ascending to descending
changes the sign of the range.
A. I only
B. II only
C. III only
D. I and II
E. I and III
DATA ANALYSIS 46
Which of the following are possible residual plots?
A. I only
B. II only
E. I, II, and III
C. III only
D. I and II
DATA ANALYSIS 47
A scatterplot of a company’s revenues versus time indicates a
possible exponential relationship. A linear regression on
y = log(revenue in $1,000) against x = years since 2005
gives ŷ = 0.75 + 0.63x with r = 0.68.
Which of the following are valid conclusions (on next slide)?
I. On the average, revenue goes up 0.63 thousand dollars
per year.
II. The predicted revenue for year 2009 is approximately
1,862 thousand dollars.
III. 46% of the variation in revenue can be explained by
variation in time.
A. I only
B. II only
C. III only
D. I and III
E. None of the above are valid conclusions.
DATA ANALYSIS 48
Given these parallel boxplots, which of the statements on
the following are true?
I. All three have the same range.
II. All three have the same interquartile range.
III. All three medians are between 8 and 12.
A. I only
D. I and III
B. II only
E. II and III
C. III only
DATA ANALYSIS 49
An AP Statistics teacher started using z-scores. On the second major exam
of the marking period, a student receives a grade with a z-score of -1.3.
What is the correct interpretation of the grade?
A. The student’s grade went down 1.3 points from the first exam.
B. The student’s grade went down 1.3 points more than the average grade
went down from the first exam.
C. The student scored 1.3 standard deviations lower on the second exam
than on the first.
D. The student scored 1.3 standard deviations lower on the second exam
than the class average on the first exam.
E. The student scored 1.3 standard deviations lower on the second exam
than the class average on the second exam.
DATA ANALYSIS 50
Given two independent random variables, X with mean 12.3
and standard deviation 0.5, and Y with mean 9.1 and standard
deviation 0.3, which of the following is a true statement?
A.
B.
C.
D.
E.
The mean of X – Y is 21.4
The median of X – Y is 3.2
The range of X – Y is 21.4
The standard deviation of X – Y is 0.8
The variance of X – Y is 0.34
DATA ANALYSIS 51
Consider the following total sales histogram. Which of
the following are true statements?
I. Each year since 1999 the total sales has increased.
II. Labeling has resulted in a misleading picture.
III. It is possible that the total sales per year decreased every
year between 1999 and 2007.
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 52
A study of weekly hours of television watched and SAT scores reports a
correlation of r = -1.18. From this information, we can conclude that:
A. Students who watch more TV tend to have lower SAT scores.
B. The fewer the hours in front of a TV, the higher a student’s SAT score.
C. There is little relationship between weekly hours of TV watched and
SAT scores.
D. There is a strong negative association between weekly hours of TV
watched and SAT scores, but it would be wrong to conclude
causation.
E. A mistake in arithmetic has been made.