hi

2.

How many of the pieces of wood have strengths less than the mean?

3.

Below is a stemplot describing the distribution of breaking strengths. What feature of the stemplot explains the fact that the mean is smaller than most of the observations?

23

0

24

1

25

26

5

27

28

7

29

30

259

31

399

32

033677

33

0237

A.

That the stemplot is symmetrical.

B.

That the stemplot is skewed to the left.

C.

That the stemplot is skewed to the right.

D.

The stemplot provides no explanation.

4.

(1.06) Where are older Americans more likely to live? Table 1.2, below, below gives the percent of residents aged 65 years and over in each of the 50 states and the District of Columbia.

Make a histogram of the percent using classes of width 1% starting at 7%. That is, the first bar covers 7.0% to 7.9%, the second covers 8.0% to 8.9%, and so on.
Select the bar graph that correctly presents the data.

A.

Graph A

B.

Graph B

C.

Graph C

D.

Graph D

(1.09) Figure 1.9 shows the distribution of the state percents of women aged 15 and over who have never been married.

Data Set

5.

The main body of the distribution is slightly skewed to the right.
There is one clear outlier, the District of Columbia.
Why is it not surprising that the percent of never-married women is higher in DC than in the 50 states?

A.

Because women in the District of Columbia are more likely to be career-oriented.

B.

Because the average percent in one state only, is likely to be quite different from the overall average percent.

C.

Because DC is a big city.

D.

There is no reasonable explanation for this statistical result.

6.

The midpoint of the distribution is the 26th largest (or smallest) value in order of percent of never-married women. In which class does the midpoint fall?

A.

The midpoint is included in the 26% and 28% bar.

B.

The midpoint is included in the 28% and 30% bar.

C.

The midpoint is included in the 22% and 24% bar.

D.

None of the above.

7.

About what is the spread (smallest to largest) of the distribution?(ignoring the outlier).

A.

From 20% to 34%.

B.

From 20% to 52%.

C.

From 0% to 34%.

D.

From 0% to 52%.

Until Congress allowed some enforcement in 2002, the thousands of foreign diplomats in New York City could freely violate parking laws.
Two economists looked at the number of unpaid parking tickets per diplomat over a five-year period ending when enforcement reduced the problem.
They concluded that large numbers of unpaid tickets indicated a “culture of corruption” in a country and lined up well with more elaborate measures of corruption.
The data set for 145 countries is too large to print here, but look at the data file on the text Web site and CD.

Data Set

The first 32 countries in the list (Australia to Trinidad and Tobago) are classified by the World Bank as “developed.” The remaining countries (Albania to Zimbabwe) are “developing.” The World Bank classification is based only on national income and does not take into account measures of social development.
Give a full description of the distribution of unpaid tickets for both groups of countries and identify any high outliers. Compare the two groups.
Does national income alone do a good job of distinguishing countries whose diplomats do and do not obey parking laws?
Follow the four-step process in reporting your work.

8.

State: Which of the options below clearly states the practical question we are trying to answer?

A.

Do diplomats violate parking laws?

B.

Why do diplomats from developing countries have more unpaid parking tickets than those from developed countries?

C.

Why do diplomats from developed countries and those from developing countries violate parking laws?

D.

Do diplomats from developed countries and those from developing countries differ in number of unpaid parking tickets?

9.

Plan: Which of the options below clearly states the statistical operations that this problem calls for?

A.

We need to find the five-number summaries of the two groups.

B.

We need to compare the mean and the standard deviations of the two groups.

C.

We need to compare the distributions, including appropriate measures of center and spread.

D.

We need to plot the data using histograms or stemplots.

10.

Solve: What should be the first step in your statistical analysis?

A.

Perform a five-number summary for each data set.

B.

Plot the data using histograms or stemplots.

C.

Plot the data using a time plot.

D.

Calculate the mean and standard deviation.

11.

As part of the solving process make stemplots for the two distributions.
Which of the following descriptions match your findings?

A.

The distributions are sharply skewed to the right and the developed countries have a high outlier.

B.

The distributions are sharply skewed to the right and they both have high outliers.

C.

The distributions are sharply skewed to the left and the developed countries have an outlier.

D.

The distributions are skewed to the right and the developed countries group is two-peaked.

12.

Which of the following numerical descriptions is the most appropriate choice for these distributions?

A.

The means and standard deviations.

B.

The medians and standard deviations.

C.

Five-number summaries.

D.

Any of these is appropriate.

13.

Give the five-number summary of the distribution of the developed countries diplomats.
Match your results below:

1.

0.4

2.

0.7

3.

0.33

4.

0.1

5.

246.2

6.

0.15

7.

4

8.

0

9.

245

10.

0.5

11.

246.5

12.

240

13.

0.3

14.

0.35

15.

0.8

16.

250

17.

0.75

18.

8

19.

7.45

20.

24

A.

Minimum

B.

Q1

C.

Median

D.

Q3

E.

Maximum

14.

Give the five-number summary of the distribution of the developing countries.
Match your results below:

1.

139.6

2.

3.2

3.

1

4.

3.7

5.

18

6.

8.4

7.

2.9

8.

5.5

9.

3.5

10.

8.1

11.

38.2

12.

49.5

13.

0

14.

60

15.

9.5

16.

117

17.

139

18.

22.80

19.

110

20.

119

15.

Conclude: What is your conclusion based on your statistical analysis?

A.

Diplomats from developing countries generally had fewer parking tickets than those from developed countries.

B.

Diplomats from developed countries generally had fewer parking tickets than those from developing countries.

C.

Diplomats tend to violate parking laws.

D.

There is no apparent difference in number of unpaid parking tickets between the two groups.

16.

The respiratory system can be a limiting factor in maximal exercise performance. Researchers from the United Kingdom studied the effect of two breathing frequencies on both performance times and several physiological parameters in swimming. Subjects were 10 male collegiate swimmers. Here are their times in seconds to swim 200 meters at 90% of race pace when breathing every second stroke in front-crawl swimming:

The standard deviation of the 10 swim times is about 8.2. The correct units for the standard deviation are

A.

no units—it’s just a number.

B.

seconds.

C.

seconds squared.

17.

Which of the following is least affected if an extreme high outlier is added to your data?

A.

The median

B.

The mean

C.

The standard deviation

18.

(1.21) How long must you travel each day to get to work? Here is a stemplot of the average travel times to work for workers in the 50 states and the District of Columbia who are at least 16 years of age and don’t work at home. The stems are whole minutes and the leaves are tenths of a minute.

The center of the distribution in the data above is close to

Data Set

A.

22 minutes

B.

23.4 minutes

C.

15.5 to 30.9 minutes

19.

(1.22) You look at real estate ads for houses in Naples, Florida. There are many houses ranging from $200,000 to $500,000 in price. The few houses on the water, however, have prices up to $15 million. The distribution of house prices will be

A.

skewed to the left.

B.

roughly symmetric.

C.

skewed to the right.

(1.24) How can we help wood surfaces resist weathering, especially when restoring historic wooden buildings? In a study of this question, researchers prepared wooden panels and then exposed them to the weather.

20.

Here are some of the variables recorded. Which of these variables are categorical and which are quantitative?

1.

Categorical variable.

2.

Quantitative variable.

A.

Type of wood (yellow poplar, pine, cedar)

B.

Type of water repellent (solvent-based, water-based)

C.

Paint thickness (millimeters)

D.

Paint color (white, gray, light blue)

E.

Weathering time (months)

(1.29) The National Survey of Student Engagement asked students at many universities, “How would you evaluate your entire educational experience at this university?” Here are the percents of senior-year students at Canada’s 10 largest primarily English-speaking universities who responded “Excellent”:

21.

The list is arranged in order of undergraduate enrollment. Make a bar graph with the bars in order of student rating.

A.

B.

C.

D.

22.

Select the most appropriate explanation why it is not correct to make a pie chart of these data.

A.

A pie chart would be inappropriate, because these percentages aren’t “shares.” That is, the percentages don’t sum to 100%.

B.

A pie chart would be inappropriate, because there is too much data to display.

C.

A pie chart would be inappropriate, because the given data is not in ascending order.

Place five observations on the line in the
Mean and Median applet
by clicking below it.

23.

Add one additional observation without changing the median. Where is your new point? In order for you to answer, number the original five points from left to right. Indicate between which points you placed your sixth point. If you placed it exactly on a certain point, then indicate that you placed it between that point and itself.

1.

Point #1

2.

Point #2

3.

Point #3

4.

Point #4

5.

Point #5

A.

The new point was placed between …

B.

and …

24.

Use the applet to convince yourself that when you add yet another observation (there are now seven in all), the median does not change no matter where you put the seventh point. Explain why this must be true.

A.

Actually this is not a true statement.

B.

The median doesn’t change because it is considered a resistant measure.

C.

This statement is true only if the new point is added exactly at the value of the median with 6 points.

D.

When we had six points, the median was between the 3rd and 4th point, but since they were coincident, it coincided with them. For seven points, the median falls on the middle point, 4th out of seven. No matter where the seventh point is added, one of the original coincident points is always the middle point out of seven.

E.

This statement is true only if the new point is added above the value of the median with 6 points. That way, the 4th point out of 6 remains the 4th point out of 7, so the median remains in place.

F.

This statement is true only if the new point is added below the value of the median with 6 points. That way, the 3th point out of 6 changes to be the 4th point out of 7, so the median remains in place.

25.

26.

Select the correct choice.
“Suppose we want to estimate the average number of chocolate chips per cookie in a batch of cookies. The collection of all cookies in the batch is known as the ____.”

Reference: StatClips: Statistics Introduction

A.

Sample

B.

Parameter

C.

Population

D.

Estimate

27.

True or False:
We are allowed to remove records that do not appear to fit in with the rest of the data to create a more uniform data set.

Reference: StatClips: Basic Principles of Exploring Data

28.

Select the correct choice.
If a histogram is considered “skewed left” which value will be greater, the median or mean?

Reference: StatClips: Exploratory Pictures for Quantitative Data

A.

Median

B.

Mean

29.

Select the correct choice.
“If you plan to work with data in your career, you need to learn something about _____.”

Reference: Snapshots: Statistics Introduction

A.

Statistics

B.

Politics

C.

Data management

D.

Communication

E.

World events