Question 1

Twelve randomly chosen students were asked how many times they had missed class during a certain semester, with this result: 2, 1, 5, 1, 1, 3, 4, 3, 1, 1, 5, 18. For this sample, which measure of center is least representative of the "typical" student?

Accepted Answer

A) Mean 
B) Median 
C) Mode 
D) Midrange

Question 2

Which is a characteristic of the standard deviation?

Accepted Answer

A) It is not greatly affected by outliers. 
B) It is measured in the same units as the mean. 
C) It measures dispersion around the median. 
D) It has a natural, concrete meaning.

Question 3

The Empirical Rule can be applied to any distribution, unlike Chebyshev's theorem.
E.R. assumes a normal population, while Chebyshev applies to any population.

Accepted Answer

A) True 
 B)False

Question 4

The Empirical Rule assumes that the distribution of data follows a normal curve.
E.R. assumes a normal population.

Accepted Answer

A) True 
 B)False

Question 5

Based on daily measurements, Bob's weight has a mean of 200 pounds with a standard deviation of 16 pounds, while Mary's weight has a mean of 125 pounds with a standard deviation of 15 pounds. Who has the smaller relative variation?

Accepted Answer

A) Bob 
B) Mary 
C) They are the same. $\overline { X ^ { * } }$ $\overline { X ^ { * } }$

Question 6

It is inappropriate to apply the Empirical Rule to a population that is right-skewed.
E.R. applies to normal populations.

Accepted Answer

A) True 
 B)False

Question 7

The mean of a population is 50 and the median is 40. Which histogram is most likely for samples from this population?

Accepted Answer

A)  Sample A 
B)  Sample B. 
C)  Sample C.

Question 8

Find the sample correlation coefficient for the following data. $$\begin{array} { | r | r | } 
\hline X & Y \
\hline 3 & 8 \
\hline 7 & 12 \
\hline 5 & 13 \
\hline 9 & 10 \
\hline 11 & 17 \
\hline 13 & 23 \
\hline 19 & 39 \
\hline 21 & 38 \
\hline
\end{array}$$

Accepted Answer

A) .8911 
B) .9132 
C) .9822 
D) .9556

Question 9

Estimate the mean exam score for the 50 students in Prof. Axolotl's class. $$\begin{array} { c r } 
\text { Score } & f \
40 \text { but less than } 50 & 6 \
50 \text { but less than } 60 & 18 \
60 \text { but less than } 70 & 14 \
70 \text { but less than } 80 & 9 \
80 \text { but less than } 90 & 3 \
\text { Total } & 50
\end{array}$$

Accepted Answer

A) 59.2 
B) 62.0 
C) 63.5 
D) 64.1

Question 10

Find the standard deviation of this sample: 4, 7, 9, 12, 15.

Accepted Answer

A) 4.550 
B) 3.798 
C) 4.278 
D) 2.997

Question 11

A data set with two values that are tied for the highest number of occurrences is called bimodal.

Accepted Answer

A) True 
 B)False

Question 12

Outliers are indicated using fences on a

Accepted Answer

A) box plot. 
B) dot plot. 
C) histogram. 
D) Pareto chart.

Question 13

The midhinge is a robust measure of center when there are outliers.

Accepted Answer

A) True 
 B)False

Question 14

The ______________ shows the relationship between two variables.

Accepted Answer

A) box plot 
B) bar chart 
C) histogram 
D) scatter plot

Question 15

Patient waiting times in the Tardis Orthopedic Clinic have a mean of 50 minutes with a standard deviation of 25 minutes. Within what range would approximately 95 percent of the waiting times lie if we were sampling a normal distribution? Do you think the distribution is likely to be normal? Explain.

Accepted Answer

The answer of Patient waiting times in the Tardis Orthopedic...

Question 16

Which statistics offer robust (resistant to outliers) measures of center?

Accepted Answer

A) Mean, midrange, mode. 
B) Median, midhinge, trimmed mean. 
C) Trimmed mean, midrange, midhinge. 
D) Mean, mode, quartiles.

Question 17

The range as a measure of variability is very sensitive to extreme data values.

Accepted Answer

A) True 
 B)False

Question 18

A certain health maintenance organization (HMO) examined the number of office visits by its members in the last year. This data set would probably be skewed to the left due to low outliers.

Accepted Answer

A) True 
 B)False

Question 19

The athletic departments at 10 randomly selected U.S. universities were asked by the Equal Employment Opportunity Commission to state what percentage of their nursing scholarships were presently held by women. The responses were 5, 4, 2, 1, 1, 2, 10, 5, 5, 5. Find the mean, median, mode, and geometric mean. Which is the most appropriate measure of central tendency? The least appropriate? Explain your answer. Is there an outlier?

Accepted Answer

The answer of The athletic departments at 10 randomly selected...

Question 20

A sample consists of the following data: 7, 11, 12, 18, 20, 22, 43. Using the "three standard deviation" criterion, the last observation (X = 43) would be considered an outlier.

Accepted Answer

A) True 
 B)False

Exam 4: Descriptive Statistics

Twelve randomly chosen students were asked how many times they had missed class during a certain semester, with this result: 2, 1, 5, 1, 1, 3, 4, 3, 1, 1, 5, 18. For this sample, which measure of center is least representative of the "typical" student?

Which is a characteristic of the standard deviation?

The Empirical Rule can be applied to any distribution, unlike Chebyshev's theorem. E.R. assumes a normal population, while Chebyshev applies to any population.

The Empirical Rule assumes that the distribution of data follows a normal curve. E.R. assumes a normal population.

Based on daily measurements, Bob's weight has a mean of 200 pounds with a standard deviation of 16 pounds, while Mary's weight has a mean of 125 pounds with a standard deviation of 15 pounds. Who has the smaller relative variation?

It is inappropriate to apply the Empirical Rule to a population that is right-skewed. E.R. applies to normal populations.

The mean of a population is 50 and the median is 40. Which histogram is most likely for samples from this population?

Find the sample correlation coefficient for the following data. $\begin{array} { | r | r | } \hline X & Y \\\hline 3 & 8 \\\hline 7 & 12 \\\hline 5 & 13 \\\hline 9 & 10 \\\hline 11 & 17 \\\hline 13 & 23 \\\hline 19 & 39 \\\hline 21 & 38 \\\hline\end{array}$

Find the standard deviation of this sample: 4, 7, 9, 12, 15.

A data set with two values that are tied for the highest number of occurrences is called bimodal.

Outliers are indicated using fences on a

The midhinge is a robust measure of center when there are outliers.

The ______________ shows the relationship between two variables.

Patient waiting times in the Tardis Orthopedic Clinic have a mean of 50 minutes with a standard deviation of 25 minutes. Within what range would approximately 95 percent of the waiting times lie if we were sampling a normal distribution? Do you think the distribution is likely to be normal? Explain.

Which statistics offer robust (resistant to outliers) measures of center?

The range as a measure of variability is very sensitive to extreme data values.

A certain health maintenance organization (HMO) examined the number of office visits by its members in the last year. This data set would probably be skewed to the left due to low outliers.

A sample consists of the following data: 7, 11, 12, 18, 20, 22, 43. Using the "three standard deviation" criterion, the last observation (X = 43) would be considered an outlier.