Question

The box-and-whisker plot below represents some data set. What percentage of the data values are greater than or equal to 17?
10
15
20
25
30
25%
25%
25%
25%
10
15
20
25
30
11
12
13
14
16
17
18
19
21
22
23
24
26
27
28
29
Between each quartile is 25, percent, of the data
Between each quartile is 25% of the data
Highlighted Interval, equals, 25, percent, plus, 25, percent, plus, 25, percent, plus, equals, 75, percent
Highlighted Interval=25%+25%+25%+=75%

Answer 1

Using the listed data: 11, 12, 13, 14, 16, 17, 18, 19, 21, 22, 23, 24, 26, 27, 28, 29

Count the values ≥ 17: 17, 18, 19, 21, 22, 23, 24, 26, 27, 28, 29 → 11 values.

There are 16 values total, so the percentage is 11/16 = 0.6875 = 68.75% (≈ 68.8%).

Your method (adding three 25% quartile blocks to get 75%) would be correct only if 17 were exactly at the first quartile boundary (Q1); here 17 is between Q1 and the median, so that shortcut doesn't apply.