In: Statistics and Probability
At one hospital there is some concern about the high turnover of nurses. A survey was done to determine how long (in months) nurses had been in their current positions. The responses (in months) of 20 nurses were as follows.
23 | 2 | 5 | 14 | 25 | 36 | 27 | 42 | 12 | 8 |
7 | 23 | 29 | 26 | 28 | 11 | 20 | 31 | 8 | 36 |
Make a box-and-whisker plot of the data. (Select the correct graph.)
Find the interquartile range. (Enter an exact number.)
IQR =
Solution: Let us use table to calculate the required output.
Number | Data(in months) | |
1 | 2 | Minimum value=2 |
2 | 5 | |
3 | 7 | |
4 | 8 | |
5 | 8 | |
1st quartile=(8+11)/2=9.5 | ||
6 | 11 | |
7 | 12 | |
8 | 14 | |
9 | 20 | |
10 | 23 | |
Median=23 | ||
11 | 23 | |
12 | 25 | |
13 | 26 | |
14 | 27 | |
15 | 28 | |
3rd quartile=(28+29)/2=28.5 | ||
16 | 29 | |
17 | 31 | |
18 | 36 | |
19 | 36 | |
20 | 42 | Maximum value=42 |
Step 1: Arrange the given data in ascending order.
2 | 5 | 7 | 8 | 8 | 11 | 12 | 14 | 20 | 23 | 23 | 25 | 26 | 27 | 28 | 29 | 31 | 36 | 36 | 42 |
Step 2: Find the median.
Median is the mean of the middle two numbers.
Median=(23+23)/2=23
Step 3: Find the first and third quartile.
The first quartile is the median of the data points to the left of the median(check in the first table)
1st quartile=(8+11)/2=9.5
The third quartile is the median of the data points to the right of the median(check in the first table)
3rd quartile=(28+29)/2=28.5
Step 4: Find minimum and maximum value
Minimum value=2
Maximum value=42
Step 5: Let us make the box plot for the above data set. I have drawn on the sheet of paper and the same is uploaded.
Step 6: IQR=Q3-Q1=28.5-9.5= 19