A standardised score is calculated as:

value minus mean, divided by standard deviation

A standardised score of $-2$ means the value is:

2 standard deviations below the mean

an average and a measure of spread, in context

14questions. Pick an answer and you'll see why right away.

Find the mean of $3, 5, 5, 7, 10$ .
Find the median of $8, 2, 5, 9, 4, 7$ .
To estimate the mean of grouped data you multiply each frequency by the class:
Coursework is weighted 30% and an exam 70%. A student scores 80 and 60. The weighted mean is:
The interquartile range is:
Which measure of spread is least affected by an outlier?
For the data $4, 6, 8$ with mean 6, the variance is:
The standard deviation is found from the variance by:
A box plot displays the minimum, lower quartile, median, upper quartile and:
A standardised score is calculated as:
A standardised score of $-2$ means the value is:
If a distribution's mean is greater than its median, it has:
Two classes have equal medians, but class X has a larger IQR. Class X is:
When comparing two data sets fully, you should always state: