One of the first topics that many Secondary 4 E-Math students learnt is a statistics chapter known as Mean and Standard Deviation (SD for short).

The nice thing about this chapter is that the 2 most important formula are both available in the E-Math (subject code: 4016) formula sheet! No memorization required, just understanding of their usage.

In this post, I will illustrate 2 methods to get the answers for mean and SD for ungrouped data (refer to example). The 2 methods are manual and calculator.

Example:

Given 15, 6, 18, 9, 2 and 4, find the mean and standard deviation.

Manual:

Mean and Standard Deviation Manual Working

Calculator, Casio fx-85MS:

1. Mode, 2(SD)
2. Enter the data in this manner, 15, M+ follows by 6, M+…
3. To get mean: Press ‘Shift’, 2, 1,=
4. To get SD: Press ‘Shift’, 2, 2,=

Here are some additional information you can obtain using the calculator:

Mean - SD from Calculator

Answers obtained through both methods are the same. By knowing these 2 methods, you can use either to double check.