PLEASE HELP ME AND MY DAUGHTER

0.85

Step-by-step explanation:

The interquartile range of any given data set is simply the difference between the Q3 and the Q1, i.e. Q3 - Q1.

Let's find the Q3 and the Q1 of the given data set: 30.8, 29.9, 30.0, 31.0, 30.1, 30.5, 30.7, 31.0

First, let's order the data given in increasing order from small to the largest value:

29.9, 30.0, 30.1, 30.5, 30.7, 30.8, 31.0, 31.0

Let's find the median:

Since the number of data set given is even number (8), our median would be the average of the 4th and 5th data value = (30.5+30.7) ÷ 2 = 30.6

Let's find Q3 and Q1

Q1 is the middle value from the median point to our left = (30.0+30.1) ÷ 2 = 30.05

Q3 is the middle value from the median point to our right = (30.8+31.0)÷2 = 30.9

Interquartile Range = 30.9 - 30.05 = 0.85