VT · Averages & Range

Calculator

In each set, one thing changes and everything else stays the same. Work them out in order and look for the pattern — the last line tells you what to notice.

①Mean: only one value changeschanging: the last value

Work out the mean of $6,\ 4,\ 8$ and the value shown.

and $2$

and $6$

and $10$

As the last value grows, the mean grows too. By how much does the mean change when the value goes up by $4$?

②Range: only the largest value changeschanging: the largest value

Work out the range of $2,\ 5,\ 8$ and the value shown.

and $10$

and $14$

and $20$

The smallest value stays $2$, so the range is just the largest value minus $2$.

③Median: only the middle value changeschanging: the middle value

Work out the median of the ordered list $1,\ 3,\ \square,\ 7,\ 9$.

$\square=4$

$\square=5$

$\square=6$

The list is already in order, so the median is always the middle number itself.

Answers · Averages & Range

Variation practice

① Mean: only one value changes

and $2$: 5and $6$: 6and $10$: 7

② Range: only the largest value changes

and $10$: 8and $14$: 12and $20$: 18

③ Median: only the middle value changes

$\square=4$: 4$\square=5$: 5$\square=6$: 6