Question

44 students completed some homework and the histogram shows information about the times taken. Work out an estimate of the interquartile range. In your working you must show the lower and upper quartiles

Answer 1

1.4×5=7

0.8×10=8

1.4×10=14

1×15=15

15+14+8+7=44

44÷4=11

LQ of 44=11

LQ=10 minutes

11×3=33

UQ= 29 minutes

The Range is 19 minutes

Step-by-step explanation:

Start with the separate boxes. So to work out the real number of students in each bracket, we do Frequency density × The difference in the bracket. (so if its 5-15 then the difference is 10)

This leads us to have the amounts of students in each bracket.

Then work out the LQ of 44 and its 11.

Then find where the 11th student's result is and in this case its in the 5-15. There is 7 already passed and 8 in 5-15. This means that the 11th is in the middle of 5-15 as 7+4=11. The middle of 5-15 is 10.

Repeat this for the UQ.

The range is UQ-LQ so 29-10=19 minutes.

Hope this helps, i'm not fully sure whether this makes sense and i've no clue what the things ive called brackets are actually called.