From 44b420aa0dd2d36a24ec8523e4b0d4219d940e1a Mon Sep 17 00:00:00 2001 From: eggy Date: Sun, 27 Sep 2020 18:23:59 -0400 Subject: [PATCH] math: clarify data transformations --- docs/mhf4u7.md | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/docs/mhf4u7.md b/docs/mhf4u7.md index 45cf530..c063a80 100644 --- a/docs/mhf4u7.md +++ b/docs/mhf4u7.md @@ -196,11 +196,15 @@ In a typical bell-shaped distribution: !!! info The **points of inflection** (when the curve changes direction) of a normal bell curve occur at $\bar{x} ± \sigma$. -### Constant operations on mean and standard deviation +### Data transformation -When adding or subtracting a constant to a whole data set, the mean is increased/decreased by that constant, but the standard deviation **does not change**. +When performing an operation with a constant value to a whole data set: + +| Operation | Effect on mean | Effect on standard deviation | +| --- | --- | --- | +| Addition/Subtraction | Increased/decreased by constant | No change | +| Multiplication/Division | Multiplied/divided by constant | Multiplied/divided by constant | -When multiplying or dividing a constant to a whole data set, both the mean and the standard deviation are multiplied or divided by that constant, respectively. ### Linear correlation and regression