Question 1

Researchers measured the length of the central retrix (R1), a flight-involved tail feather, in 21 female long-tailed finches. A boxplot of the length, in millimeters (mm), is given here:
 Based on this boxplot, to which value is the interquartile range closest?

Accepted Answer

A) 10 mm 
B) 25 mm 
C) 60 mm 
D) 70 mm

Question 2

A maze experiment uses 24 lab rats of various ages, as summarized here:
$$\begin{array} { | l | l | } 
\hline \text { Age (in months) } & \text { Number of rats } \
\hline 2 & 4 \
\hline 3 & 6 \
\hline 4 & 6 \
\hline 5 & 4 \
\hline 7 & 3 \
\hline 9 & 1 \
\hline
\end{array}$$ What is the median rat age (in months) for this maze experiment?

Accepted Answer

A) 3.5 
B) 4 
C) 4.5 
D) 5

Question 3

A sample was taken of the metabolic rates of men participating in a study regarding diets. The following boxplot depicts these rates (measured in kilocalories per 24 hours).
Which of the following statements would be true if each person in this data set increased his rate by 120 kilocalories per 24 hours?

Accepted Answer

A) The median would increase by 120. 
B) The first quartile would decrease by 60. 
C) The third quartile would increase by 60. 
D) The interquartile range would increase by 120.

Question 4

Brown tree snakes are an invasive species causing huge environmental and financial damage in Guam. In June 2000, researchers captured 504 brown tree snakes on Guam's Andersen Air Force Base. On average, the snakes weighed 121 g, and their weights ranged from 23 to 663 g at capture. From this information, what can we conclude about the shape of the distribution of brown tree snake masses?

Accepted Answer

A) It must be roughly symmetric. 
B) It must be left-skewed, have a low outlier, or both. 
C) It must be right-skewed, have a high outlier, or both. 
D) It must be multimodal (multiple-peaked).

Question 5

In a study of the function of pectoral fins in fish, a graduate student examined 7 fish with the following lengths (in centimeters, cm):
30 28 29 27 31 25 29
What is the first quartile for these data?

Accepted Answer

A) 27 cm 
B) 27.5 cm 
C) 28 cm 
D) 28.5 cm

Question 6

A sample of 20 endangered species was obtained and the length of time (in months) since being placed on the list was recorded for each species. The ordered data follow:
52, 54, 58, 59, 59, 60, 60, 63, 65, 66, 67, 68, 69, 73, 74, 77, 78, 79, 79, 98
What is the first quartile of the length of time (in months) since being placed on the list for these 20 species?

Accepted Answer

A) 5 
B) 59.5 
C) 74 
D) 75.5

Question 7

The following histogram shows the yearly number of unprovoked attacks by alligators on people in Florida over a 33-year period.
 What must be the median yearly counts of alligator attacks?

Accepted Answer

A) A value in class 4 to 8 
B) A value in class 8 to 12 
C) Exactly 12 
D) A value in class 12 to 16

Question 8

In a study of the function of pectoral fins in fish, a graduate student examined 7 fish with the following lengths (in centimeters, cm):
30 28 29 27 31 25 29
What is the variance of these 7 fish lengths?

Accepted Answer

A) 1.41 cm 
B) 1.99 cm2 
C) 3.39 cm2 
D) 3.95 cm2

Question 9

Geckos are lizards with specialized toe pads that enable them to easily climb all sorts of surfaces. A research team examined the adhesive properties of 7 Tokay geckos. Following are the toe-pad areas (in square centimeters, cm²) for this sample: 5.6 4.9 6.0 5.1 5.5 5.1 7.5 Rounded to two decimal places, what is the mean toe-pad area in this sample of geckos?

Accepted Answer

The answer of Geckos are lizards with specialized toe pads...

Question 10

A sample of 20 endangered species was obtained and the length of time (in months) since being placed on the list was recorded for each species. The ordered data follow:
52, 54, 58, 59, 59, 60, 60, 63, 65, 66, 67, 68, 69, 73, 74, 77, 78, 79, 79, 98
Which value would need to be exceeded for a data point to be considered an outlier when using the 1.5 × IQR rule?

Accepted Answer

A) 75.5 
B) 83.5 
C) 91.5 
D) 99.5

Question 11

The following dotplot shows the migraine intensity (on a scale of 1 to 10) for 29 adults suffering from recurring migraines.
 What is the five-number summary for this data set?

Accepted Answer

A) 7, 8, 9, 10, 10 
B) 7, 8, 8.5, 9, 10 
C) 7, 7.5, 8.5, 9.5, 10 
D) 7, 7.5, 8.5, 9, 10

Question 12

Here is the ordered data of body temperatures (in degrees Fahrenheit) for 65 healthy adult women:
96.4, 96.7, 96.8, 97.2, 97.2, 97.4, 97.6, 97.7, 97.7, 97.8, 97.8, 97.8, 97.9, 97.9, 97.9,
98.0, 98.0, 98.0, 98.0, 98.0, 98.1, 98.2, 98.2, 98.2, 98.2, 98.2, 98.2, 98.3, 98.3, 98.3,
98.4, 98.4, 98.4, 98.4, 98.4, 98.5, 98.6, 98.6, 98.6, 98.6, 98.7, 98.7, 98.7, 98.7, 98.7,
98.7, 98.8, 98.8, 98.8, 98.8, 98.8, 98.8, 98.8, 98.9, 99.0, 99.0, 99.1, 99.1, 99.2, 99.2,
99.3, 99.4, 99.9, 100.0, 100.8
What is the third quartile of body temperatures for this data set?

Accepted Answer

A) 98.8 
B) 99.0 
C) 99.5 
D) 99.9

Question 13

The following dotplot shows the migraine intensity (on a scale of 1 to 10) for 29 adults suffering from recurring migraines.
What is the median migraine intensity in this sample?

Accepted Answer

A) 8 
B) 8.5 
C) 9 
D) Impossible to determine

Question 14

In a study of the function of pectoral fins in fish, a graduate student examined 7 fish with the following lengths (in centimeters, cm):
30 28 29 27 31 25 29
What is median fish length?

Accepted Answer

A) 27 cm 
B) 28 cm 
C) 28.5 cm 
D) 29 cm

Question 15

Geckos are lizards with specialized toe pads that enable them to easily climb all sorts of surfaces. A research team examined the adhesive properties of 7 Tokay geckos. Following are the toe-pad areas (in square centimeters, cm²) for this sample: 5.6 4.9 6.0 5.1 5.5 5.1 7.5 What is the value of the interquartile range for these data?

Accepted Answer

The answer of Geckos are lizards with specialized toe pads...

Question 16

A study of freely forming groups in bars throughout Europe examined the number of individuals found in groups that were laughing together. A summary of the 501 groups examined is shown here:
 $$\begin{array} { | l | l | } 
\hline \text { Group size } & \text { Number of groups } \
\hline 2 & 254 \
\hline 3 & 168 \
\hline 4 & 52 \
\hline 5 & 21 \
\hline 6 & 6 \
\hline
\end{array}$$ What is the median group size?

Accepted Answer

The answer of A study of freely forming groups in...

Question 17

Here is the ordered data of body temperatures (in degrees Fahrenheit) for 65 healthy adult women:
96.4, 96.7, 96.8, 97.2, 97.2, 97.4, 97.6, 97.7, 97.7, 97.8, 97.8, 97.8, 97.9, 97.9, 97.9,
98.0, 98.0, 98.0, 98.0, 98.0, 98.1, 98.2, 98.2, 98.2, 98.2, 98.2, 98.2, 98.3, 98.3, 98.3,
98.4, 98.4, 98.4, 98.4, 98.4, 98.5, 98.6, 98.6, 98.6, 98.6, 98.7, 98.7, 98.7, 98.7, 98.7,
98.7, 98.8, 98.8, 98.8, 98.8, 98.8, 98.8, 98.8, 98.9, 99.0, 99.0, 99.1, 99.1, 99.2, 99.2,
99.3, 99.4, 99.9, 100.0, 100.8
What is the first quartile of body temperatures for this data set?

Accepted Answer

A) 97.5 
B) 97.6 
C) 97.9 
D) 98.0

Question 18

Here is the ordered data of body temperatures (in degrees Fahrenheit) for 65 healthy adult women:
96.4, 96.7, 96.8, 97.2, 97.2, 97.4, 97.6, 97.7, 97.7, 97.8, 97.8, 97.8, 97.9, 97.9, 97.9,
98.0, 98.0, 98.0, 98.0, 98.0, 98.1, 98.2, 98.2, 98.2, 98.2, 98.2, 98.2, 98.3, 98.3, 98.3,
98.4, 98.4, 98.4, 98.4, 98.4, 98.5, 98.6, 98.6, 98.6, 98.6, 98.7, 98.7, 98.7, 98.7, 98.7,
98.7, 98.8, 98.8, 98.8, 98.8, 98.8, 98.8, 98.8, 98.9, 99.0, 99.0, 99.1, 99.1, 99.2, 99.2,
99.3, 99.4, 99.9, 100.0, 100.8
Which value would need to be exceeded for a data point to be considered an outlier when using the 1.5 × IQR rule?

Accepted Answer

A) 99.6 
B) 99.8 
C) 100.0 
D) 100.8

Question 19

The distribution of ages of people in a class (to the nearest year) is as follows:
$$\begin{array} { | l | l | l | l | l | l | l | l | l | l | } 
\hline \text { Age } & 18 & 19 & 20 & 21 & 22 & 23 & 24 & 25 & 32 \
\hline \text { Number of students } & 14 & 120 & 200 & 200 & 90 & 30 & 10 & 2 & 1 \
\hline
\end{array}$$ What is TRUE about the median age (to the nearest year) of this distribution?

Accepted Answer

A) It must be 20. 
B) It could be any number between 19 and 21. 
C) It must be 21. 
D) It could be any number between 20 and 21.

Question 20

A sample was taken of the metabolic rates of men participating in a study regarding diets. The following boxplot depicts these rates (measured in kilocalories per 24 hours).
Based on this boxplot, to which value is the interquartile range closest?

Accepted Answer

A) 75 
B) 175 
C) 200 
D) 500

Exam 2: Describing Quantitative Distributions With Numbers

Researchers measured the length of the central retrix (R1) , a flight-involved tail feather, in 21 female long-tailed finches. A boxplot of the length, in millimeters (mm) , is given here: Based on this boxplot, to which value is the interquartile range closest?

In a study of the function of pectoral fins in fish, a graduate student examined 7 fish with the following lengths (in centimeters, cm) : 30 28 29 27 31 25 29 What is the first quartile for these data?

The following histogram shows the yearly number of unprovoked attacks by alligators on people in Florida over a 33-year period. What must be the median yearly counts of alligator attacks?

In a study of the function of pectoral fins in fish, a graduate student examined 7 fish with the following lengths (in centimeters, cm) : 30 28 29 27 31 25 29 What is the variance of these 7 fish lengths?

The following dotplot shows the migraine intensity (on a scale of 1 to 10) for 29 adults suffering from recurring migraines. What is the five-number summary for this data set?

The following dotplot shows the migraine intensity (on a scale of 1 to 10) for 29 adults suffering from recurring migraines. What is the median migraine intensity in this sample?

In a study of the function of pectoral fins in fish, a graduate student examined 7 fish with the following lengths (in centimeters, cm) : 30 28 29 27 31 25 29 What is median fish length?

A sample was taken of the metabolic rates of men participating in a study regarding diets. The following boxplot depicts these rates (measured in kilocalories per 24 hours) . Based on this boxplot, to which value is the interquartile range closest?