Question

In a recent issue of the IEEE Spectrum, 84 engineering conferences were announced. Four conferences lasted two days. Thirty-six lasted three days. Eighteen lasted four days. Nineteen lasted five days. Four lasted six days. One lasted seven days. One lasted eight days. One lasted nine days. Let X = the length (in days) of an engineering conference.

A. Organize the data in a chart. (Round your answers to four decimal places.)

• X	Frequency	Relative Frequency	Cumulative Relative Frequency
  2
  3
  4
  5
  6
  7
  8
  9

B. Find the median.
_____ days

Find the first quartile.
_____ days

Find the third quartile.
_____ days

C. Find the 85th percentile.

_____ days

D. Find the 10th percentile.
_____ days

E. Construct a box plot of the data.

F. The middle 50% of the conferences last from ____ days to ____ days.

G. Calculate the sample mean of days of engineering conferences. (Round your answer to two decimal places.)
_____ days

H. Calculate the sample standard deviation of days of engineering conferences. (Round your answer to two decimal places.)
_____ days

I. Find the mode.
_____ days

J. If you were planning an engineering conference, which would you choose as the length of the conference: mean, median, or mode? Choose the correct answer and explain why you made that choice.

1. I would choose the mode because almost half of the conferences lasted 3 days.

2. I would choose the median because half of the conferences lasted fewer than 4 days and half of them lasted longer than 4 days.     

3. I would choose the median because all the conferences lasted from 2 to 9 days, so 4 days would represent a value close to the center of the data.

4. I would choose the mean because it represents the average length of a conference.

K. Give two reasons why you think that three to five days seem to be popular lengths of engineering conferences. (Choose the two that apply.

1. A conference that lasts 9 days is not effective.

2. The mean, median, and mode are within this range.

3. Engineering is boring, so people do not want to spend many days at a conference.

4. 50% of the data values range from 3 to 5 days.

Answer 1

Boxplot image