# Data Summaries resources

### 3. Teach Yourself Worksheets (4)

Calculating the Mean, Median and Mode (Worksheet)

This teach yourself worksheet explains how to calculate the mean, median and mode, which are the most commonly used measures of central tendancy or average for a data set.

Calculating the POPULATION Variance and Standard Deviation (Workseet)

This teach yourself worksheet explains how to calculate the POPULATION variance and standard deviation. Note: this worksheet uses a divisor of "n" which assumes you have data on every member of the population. If you only have a sample then use the divisor "n-1" instead.

Estimating the Mean from Grouped Data (Worksheet)

This teach yourself worksheet explains how to estimate the mean from a grouped frequency table. For example, in a survey you may have asked participants to indicate an age range rather than asking their actual age.

Estimating the POPULATION Variance and Standard Deviation from Grouped Data (Worksheet)

This teach yourself worksheet explains how to estimate the POPULATION variance and standard deviation from grouped frequency data. For example, in a survey you may have asked participants to indicate an age range rather than asking their actual age. Note: this worksheet uses a divisor of "n" which assumes you have data on every member of the population. If you only have a sample then use the divisor "n-1" instead.