Question

.

For the following data set, find Q1, Q2, Q3 and the interquartile range.

15, 12, 23, 15, 7, 8, 21, 10, 12, 14, 16, 24, 19
1.
Interquartile Range
2.
Q3
3.
Q2
4.
Q1
a.
15
b.
9
c.
20
d.
11

Answer 1

To find Q1, Q2, Q3, and the interquartile range (IQR) of a data set, we need to first arrange the data in numerical order. For the given data set, the ordered data is:

7, 8, 10, 12, 12, 14, 15, 15, 16, 19, 21, 23, 24

To find Q1, we need to find the median (Q2) of the lower half of the data. The lower half of the data is:

7, 8, 10, 12, 12, 14

There are 6 values in the lower half of the data, so the median (Q2) is the average of the 3rd and 4th values, which is (10 + 12) / 2 = 11. Therefore, Q1 = 11.

To find Q3, we need to find the median (Q2) of the upper half of the data. The upper half of the data is:

15, 15, 16, 19, 21, 23, 24

There are 7 values in the upper half of the data, so the median (Q2) is the fourth value, which is 19. Therefore, Q3 = 19.

To find the IQR, we need to subtract Q1 from Q3. The IQR is equal to Q3 - Q1 = 19 - 11 = 8.

The correct answers are:

1. Interquartile Range = 8

2. Q3 = 19

3. Q2 = 11

4. Q1 = 8

Therefore, the correct answer choices are:

a. 15 (incorrect)

b. 9 (incorrect)

c. 20 (incorrect)

d. 11 (correct)