Deck 3: Displaying Data

Question 1

Outliers are

A) extreme or unusual values.
B) the lowest value in a data set.
C) the lowest and highest scores in a data set.
D) all of the above

Answer 1

extreme or unusual values.

Question 2

A stem-and-leaf display is often

A) a simplified representation of the underlying data.
B) a quick way to draw a histogram.
C) more informative than the corresponding histogram.
D) all of the above

Answer 2

all of the above

Question 3

The data in the previous question show a much higher incidence of low birth weight babies from mothers who smoke. This finding is likely to be a reliable one because

A) everyone knows that smoking is a bad thing.
B) the smokers rate of low birth weight is twice that of the non-smokers.
C) the pattern of differences occurs reliably over each of 5 years.
D) there is a general increase in low birth weight over the years.

Answer 3

the pattern of differences occurs reliably over each of 5 years.

Question 4

Assume that you have a set of data with 70 values spread fairly evenly between 0 and 100. The optimal number of categories for a histogram of these data would be approximately

A) 4
B) 10
C) 25
D) 50

Question 5

In the text there was a stem-and-leaf display showing the performance of students who attended class regularly and those who often skipped class. This display illustrated

A) that poor attendees did more poorly than good attendees.
B) the shape of the two distributions.
C) the dispersion of the two distributions.
D) all of the above

Question 6

Someone asks you if you have seen the movie Titanic . Before you answer, you look back into your memory for all of the movies you have ever seen and review the titles one at a time. This is an example of

A) parallel processing
B) frequent processing
C) sequential processing
D) sensory memory

Question 7

Which of the following is the least important characteristic of graphics?

A) clarity
B) beauty
C) simplicity
D) neatness

Question 8

Assume that we had the following set of data:

T hese data would most likely be characterized as

A) positively skewed.
B) normal.
C) negatively skewed.
D) uniformly distributed.

Question 9

If you created a stem-and-leaf display of the math SAT scores of all entering students in a large Midwestern state university, the leaves would most likely be

A) the numbers 2 through 8.
B) the numbers 0 through 9 (with code |6|5 = 650).
C) t, f, c.
D) the symbols * and .

Question 10

The following graphic is adapted from one in Wainer (1984), plotting the number of private and public elementary schools (in thousands) in the U.S. between 1930 and 1970. Wainer was presenting it as a bad example, and I have made it worse. What is bad about this example?

​

A) The three dimensional effect only makes the graph harder to read.
B) Any change in the number of private schools is difficult to see.
C) The time intervals on the abscissa are too broad.
D) a and b but not c

Question 11

The "real lower limit" of an interval in a histogram is

A) the lowest integer value for scores in that interval.
B) the midpoint of the interval.
C) the lowest continuous value that would be rounded up into that interval.
D) the smallest width of the interval.

Question 12

If you created a stem-and-leaf display of the math SAT scores of all entering students in a large Midwestern state university, the stem would best be

A) the numbers 0 through 10.
B) the numbers 200 through 800.
C) the numbers 2 through 8.
D) it is impossible to tell

Question 13

Inglehart (1990) presented data on the mean Satisfaction with Life scores for 24 developed countries. These data follow:

A histogram of these data would be
​

A) reasonably symmetric.
B) positively skewed.
C) very bimodal.
D) impossible to draw.

Question 14

On October 25, 1978 the Washington Post presented a graphic showing the declining purchasing power of the U.S. dollar. What was worth $1 in 1958 was worth only $0.44 in 1978. They illustrated the decline in value by showing a dollar that was 3 inches by 1 inch in 1959, and one that was 1.32 inches (44% of 3 inches) by .44 inches in 1978. What is wrong with this kind of a display?

A) You can't equate dollars in 1958 with dollars in 1978.
B) The dollar actually increased in purchasing power over that period of time.
C) There is nothing wrong with doing this.
D) The area of the dollar is reduced by more than .44%.

Question 15

"5s" represents what numbers on a stem-and-leaf display according to Tukey?

A) 50-51
B) 52-53
C) 54-55
D) 56-57

Question 16

Frequency distributions are used

A) as a first step in examining data.
B) as a screening device to identify questionable values.
C) to organize data.
D) all of the above

Question 17

On a recent fundraising drive, most of the 30 volunteers raised between $10 and $50 each. However, Brian and Karen each raised over $100. Which of the following is true?

A) The amounts of money raised by Brian and Karen are outliers.
B) The data would best be represented three-dimensionally.
C) The data appear negatively skewed.
D) The data should be represented on a back-to-back stem-and-leaf display.

Question 18

For the data referred to in the previous question, the distribution would best be called

A) bimodal.
B) unimodal.
C) symmetric.
D) balanced.

Question 19

The Center for Disease Control has published statistics relating maternal smoking to low birth weight. The data follow in terms of the percentage of birth weights

Which of the following ways of presenting the data would be most informative?
​

A) a histogram
B) a time series graph with a line for smokers and one for non-smokers
C) two pie charts
D) a stem-and-leaf display

Question 20

When we plot a histogram, the values on the X axis are

A) the real lower limits and real upper limits
B) the midpoints
C) the integers closest to the boundaries.
D) any of the above, depending on what makes the most sense at the time

Question 21

Displaying data on graphs

A) can aid communication of results to an audience.
B) can organize data in logical order.
C) can be done with computers.
D) all of the above

Question 22

In deciding on the number of stems to use in a stem and leaf display,

A) you should always break the stems into 5 stems per every 10 units.
B) you should normally make all of the stems the same width.
C) you should generally use 10 stems in all.
D) you should disregard the frequencies of the data.

Question 23

The real lower limit and the real upper limit of the interval 40-49 are

A) 39.5 and 49.5.
B) 40 and 49.
C) 40 and 50.
D) 39 and 50.

Question 24

The following is a frequency distribution.
​

Question 25

Boxplots are graphical displays that

A) emphasize the basic characteristics of the data.
B) focus on the median and spread of the data.
C) allow us to visually see how two or more distributions compare.
D) all of the above

Question 26

Which of the following distributions can be symmetric?

A) unimodal
B) bimodal
C) normal
D) all of the above

Question 27

A normal distribution must

A) have outliers.
B) be symmetric.
C) be positively skewed.
D) be negatively skewed.

Question 28

To get an accurate idea about the shape of a distribution,

A) relatively large samples of data are needed.
B) computer programs are needed.
C) three-dimensional plots are usually helpful.
D) stem-and-leaf displays are the only accurate methods of presentation.

Question 29

Kurtosis is

A) the constant in the midpoint equation when graphing histograms.
B) a little-used measure of the shape of a distribution.
C) a computer graphics program.
D) a disease common to people named Kurt.

Question 30

If the distribution of the ages of people were positively skewed, which of the following is most likely correct?

A) There are about the same number of young people as old people.
B) There are more young people than old people.
C) There are more old people than young people.
D) none of the above

Question 31

The onset of eating disorders was shown to occur most often during puberty and during the late teen years in girls. A distribution of the frequencies of onset of eating disorders by age would most likely be

A) unimodal.
B) normal.
C) bimodal.
D) all of the above

Question 32

In the above data set, the outliers would most likely be

A) 94 and 99.
B) 36 and 99.
C) 36 and 42.
D) There are no outliers.

Question 33

Given the following numbers, 10, 25, 37, and 40, the leading digits are 1, 2, 3, and 4.

Question 34

A negatively skewed distribution

A) has a tail pointing to the left.
B) has a tail pointing to the right.
C) is symmetric.
D) is also positively skewed.

Question 35

In making plots of data, which of the following rules is true?

A) Three-dimensional plots should never be used.
B) Rules of graphical presentation are prescriptive and should never be broken.
C) The ultimate goal in making plots is to make data attractive.
D) The point of representing data graphically is better communication.

Question 36

A data set of test scores consisted of the following:

On a stem-and-leaf display, the values of the tens digits (3 - 9) are
​

A) the trailing digits.
B) the leaves.
C) the less significant digits.
D) the stems.

Question 37

Assume that you have a set of data with 70 values spread fairly evenly between 0 and 100. The optimal number of categories for a histogram of these data would be approximately

A) 4
B) 50
C) 10
D) 25

Question 38

The leading digits are the leaves in a stem and leaf plot.

Question 39

The above data set appears

A) positively skewed.
B) negatively skewed.
C) normally distributed.
D) bimodal.

Question 40

A frequency distribution

A) displays the average of each score received.
B) offers no more information than a collection of raw data.
C) counts the number of times each score is received.
D) does none of the above.

Question 41

When a variable has many values, and each value occurs rarely, a stem-and-leaf plot is preferable to a histogram.

Question 42

The next six questions are based on the following data.
Create a frequency distribution for these data.

Question 43

The next six questions are based on the following data.
Create a stem and leaf plot for these data.

Question 44

The previous graph is symmetrical.

Question 45

Skewness refers to how symmetrical or assymetrical a distribution is.

Question 46

The next six questions are based on the following data.
Which graphical technique do you think displays the data least effectively? Why?

Question 47

An outlier refers to data that falls toward the middle of a distribution.

Question 48

The next six questions are based on the following data.
Where do the data tend to cluster?

Question 49

Answer the following questions based on the graph below.

a. Is the graph symmetrical?
b. Is the graph unimodal or bimodal?
c. Do the data appear skewed?   If so, positively or negatively?
d. Do there appear to be outliers? If so, for what values?

Question 50

The next six questions are based on the following data.
Is the distribution symmetrical?

Question 51

Answer the following questions based on the graph below.

a. Is the graph symmetrical?
b. Is the graph unimodal or bimodal?
c. Do the data appear skewed?   If so, positively or negatively?
d. Do there appear to be outliers? If so, for what values?

Question 52

In a frequency distribution, the number of observations that fall within an interval is plotted.

Question 53

The following graph is unimodal.

Question 54

Draw a distribution that is negatively skewed.

Question 55

87 is the midpoint of the interval from 85 to 89.

Question 56

Use two terms to describe the following data.

Question 57

The next six questions are based on the following data.
Create a histogram for these data using an interval of 5 (e.g., 0 to 5, 6 to 10).