1. Bell Work – Measures of Variability, Table, Histogram, and Box Plot
Wednesday, March 26, 2014

2. Use the following information to answer questions 11 and 12
Use the following information to answer questions 11 and 12. The number of members for five school clubs are listed in the table.
4-H
Art
Drama
Beta
FFA 52 28 64 46 30
What is the interquartile range (IQR) and what does it tell you about the data?
12. What is the mean absolute deviation (MAD) of the data and what does this indicate about the number of members of each club?

3. Use the following information to answer questions 11 and 12
Use the following information to answer questions 11 and 12. The number of members for five school clubs are listed in the table.
4-H
Art
Drama
Beta
FFA 52 28 64 46 30
What is the interquartile range (IQR) and what does it tell you about the data?
The IQR is 29 which indicates the data is spread out. Q3

4. Use the following information to answer questions 11 and 12
Use the following information to answer questions 11 and 12. The number of members for five school clubs are listed in the table.
4-H
Art
Drama
Beta
FFA 52 28 64 46 30
12. What is the mean absolute deviation (MAD) of the data and what does this indicate about the number of members of each club?
The MAD is 12 which indicates the average difference of members of each club to the mean. Having a MAD of 12 also means the data is somewhat spread out.

5. In which time interval is the median?
The following histogram shows the amount of time people spent on a single phone call.
How many people spent 10 or more minutes on a phone call?
In which time interval is the median?

6. The following histogram shows the amount of time people spent on a single phone call.
How many people spent 10 or more minutes on a phone call?
In which time interval is the median?
100 people
With 150 values in the data set, the median is between the 75th and 76th value

7. The following box plot shows the weight of different cats.
a. Copy the box plot.
Then, identify the following:
lower (minimum) extreme value
upper (maximum) extreme value
median (2nd quartile)
lower (1st) quartile
upper (3rd) quartile
interquartile range (IQR)
mean absolute deviation (MAD)
b. Analyze the variability (describe the relationships between the quartiles). Is there more variability in the lower or upper half of the data?

8. The following box plot shows the weight of different cats.
Lower (first) quartile
Median
Upper (third) quartile
Upper (maximum)extreme value
Lower (minimum)extreme value
IQR = 13 – 8 = 5
MAD cannot be found because the entire data set is not seen in a box plot.
a. Copy the box plot. Then, identify the following:
lower (minimum) extreme value = 6
upper (maximum) extreme value = 22
median (2nd quartile) = 11
lower (1st) quartile = interquartile range (IQR) = 5
upper (3rd) quartile = mean absolute deviation (MAD) = N/A

9. The following box plot shows the weight of different cats.
When comparing the first and third quartile, the range from the median is close. The median to the first quartile is 11-8 = 3. The range from the median to the third quartile is 13 – 11 = 2. This means the difference between the data in these sections are about the same. Greater variability can be seen in the upper half of the data from the third quartile to the upper extreme, = 9. The range of data from the lower quartile to the lower extreme shows less variation, 8-6 = 2. The data in the lower half are grouped more closely together. The data in the upper half are more spread out.
b. Analyze the variability (describe the relationships between the quartiles). Is there more variability in the lower or upper half of the data?

10. The following box plot shows the test scores of 15 students.
15.c. Copy the box plot and describe the spread of the data.
The box plot shows that the score are very evenly
distributed. The interquartile range (middle half of the
scores) is 10. Both the bottom and top quarter of the scores
also have a range of 10 from 75 to 85 and 85 to 95,
respectively. Both the minimum and maximum values are
20 points from the median.