You must know how to calculate the standard deviation from given summary data using the formula: \displaystyle \sqrt{\frac{\sum x^2}{n} - \bar{x}^2}

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## Glossary

### standard deviation

The square root of the variance; a measure of dispersion.

### union

The union of two sets A and B is the set containing all the elements of A and B.

**Full Glossary List**

More in this topic

1 Calculate standard deviation

2 Exam Question

3 Exam Question

4 Exam Question

5 Exam Question

6 Variance

7 Standard deviation

8 Calculate standard deviation 2

9 Standard deviation on a GDC

10 Calculate standard deviation 3

11 Standard deviation on a GDC 2

12 Exam Question

13 Exam Question

14 Interquartile range

15 Interquartile range on a GDC

16 Exam Question

17 Skewness

18 Exam Question

19 Exam Question

20 Exam Question

21 Skewness O-test

22 Summary stats on a GDC

23 Timed O-test

24 Exam O-test 1

25 Exam O-test 2

26 Exam timed O-test