Find the mean of \( 4, 7, 9, 12, 8 \).
Sum \( = 40 \). Mean \( = 8 \).
Averages & Charts
8 exam-style questions on mean, median, mode, range and interpreting charts.
3 Easy 3 Medium 2 Hard
Find the median of \( 3, 8, 2, 9, 5 \).
Ordered: \( 2, 3, 5, 8, 9 \). Median \( = 5 \).
Find the mode and range of \( 2, 5, 3, 5, 7, 5, 1 \).
Mode \( = 5 \). Range \( = 7 - 1 = 6 \).
Five numbers have a mean of \( 12 \). Four of them are \( 10, 11, 13, 14 \). Find the fifth number.
Sum of five \( = 60 \). Sum of four \( = 48 \). Fifth \( = 12 \).
In a frequency table, scores 1, 2, 3, 4 have frequencies 3, 5, 4, 2. Find the mean.
Total frequency \( = 14 \). Sum of scores \( = 1\times3 + 2\times5 + 3\times4 + 4\times2 = 3+10+12+8 = 33 \). Mean \( = \dfrac{33}{14} \approx 2.36 \).
The median of a set of 9 ordered numbers is the 5th. The numbers are \( 2, 4, 5, 6, x, 9, 11, 12, 15 \) and the median is \( 8 \). Find \( x \).
5th value is \( x \), so \( x = 8 \).
Grouped data: class 0–10 (freq 4), 10–20 (freq 6), 20–30 (freq 10). Estimate the mean using midpoints.
Midpoints 5, 15, 25. Sum \( = 5\times4 + 15\times6 + 25\times10 = 20+90+250 = 360 \). Total freq \( = 20 \). Mean \( \approx 18 \).
Two groups: Group A has 10 students with mean score 60. Group B has 15 students with mean score 70. Find the combined mean.
Total A \( = 600 \), total B \( = 1050 \). Combined mean \( = \dfrac{1650}{25} = 66 \).