Quiz 1.6-1.9

Which of the following can be used to describe the spread of a distribution? Select all that apply.

• range

• interquartile range

• standard deviation

• standard error

• z-scores

• the shape is skewed to the right
• the shape is symmetric
• the shape is skewed to the left
• 75% of the data is between 1-8

Which profession had the greatest range of salaries?

• Nuclear engineer

• Police officer

• Musician

• Impossible to tell

Data points in the first quartile are between which two points?

• 6 and 8

• 8 and 12

• 12 and 15

• 15 and 19

The box-and-whisker plot displays the number of inches of snowfall last year for 14 cities. Each city had a different amount of snowfall.

What percent of the cities had more than 64 inches of snow?

• 64%

• 50%

• 75%

• 70%

Which box and whisker plot has the highest median?

• Top plot
• Bottom plot

Which statement is correct?

A. The IQR of store A is greater than the IQR of store B.

B. The IQR of store B is greater than the IQR of store A.

• A

• B

Answer explanation

IQR = Q3 - Q1.

Q3 is the right of the box and Q1 is the left line of the box.

Store A: IQR = 300 - 150 = 150

Store B: IQR = 400 - 225 = 175.

Store B has a little higher IQR at 175 vs 150 for store A.

The percentile represents the....

• percent of data values that are below.
• percent of data values that are above.
• number of data values that are below.
• number of data values that are below.

If I tell you that you scored at the 55th percentile on your final exam, you would know:

• 55% of the class scored the same or worse than you did

• You earned a 55% on the exam

• You failed the exam

• 45% of the class scored worse than you did

Find the median, first quartile, third quartile, and interquartile range of the data.

203, 183, 212, 181, 157, 204, 189, 190

• Median: 189

  First Quartile: 182

  Third Quartile: 203

  IQR: 21

• Median: 189.5

  First Quartile: 182

  Third Quartile: 203

  IQR: 21

• Median: 189

  First Quartile: 182

  Third Quartile: 203.5

  IQR: 21.5

• Median: 189.5

  First Quartile: 182

  Third Quartile: 203.5

  IQR: 21.5