Maths: Numerical Measures (GCSE, Edexcel)

Mean

Mean

sum of all values / number of values

Median

Middlemost value

Mode

Most common value. If there is a tie, there is no mode.

Range

largest value - smallest value

Place of a median (not in a diagram)

(number of values + 1) / 2

Place of a median (in a diagram)

number of values / 2

Mean from a frequency table strategy (ungrouped)

• Find the sum of the frequencies (Σf)

• Do the frequency x data point for each row (fx)

• Find the sum of fx (Σfx)

• The mean is Σfx / Σf

Median from a frequency table strategy

• Find the place of the median. This is not a diagram. The total number of values is Σf.

• Keep a running total of the frequencies.

• Identify the data points that the median is between. The higher one is the median.

Mode from a frequency table strategy

The data point with the highest frequency is the mode.

Median and Mode from a grouped frequency table

Unchanged - you’ll never be asked to find the exact estimate, only class interval.

Mean from a frequency table strategy (grouped)

• Find the sum of the frequencies (Σf)

• Find the midpoints of all the class intervals (m)

• Do the frequency times the midpoint for each row (fm)

• Find the sum of fm (Σfm)

• The mean is Σfm / Σf