*Calculate and interpret the mean and standard deviation of data and use these to compare data sets. Investigate the effect of individual data values including outliers, on the standard deviation(VCMSP372)*

**LO: To calculate the Z-Score for a data set.**

**Know:**

- How to calculate the mean of a data set.
- How to calculate the standard deviation of a data set.

**Understand:**

That Z-scores helps us to locate a data point within a standard distribution curve.

**Do:**

- I can calculate the Z-score for a data point.

*Visual Representations*

*Notes*

### A Z-score is the number of standard deviations from the mean a data point is. It can positive or negative depending on whether the data point is above or below the mean respectively. Z-scores can only be applied to data with a normal distribution curve.

### Z-scores range from -3 to +3.

### This histogram is normally distributed. It is also known as a “*bell curve*“.

### This histogram is *not normally distributed*. You can not find a Z-score of a data point when the histogram is not a normally distributed curve.

*Z-Score Formula*

### To find the Z-score of a data point, you just have to use the data point then subtract the mean and then divide it by the standard deviation.

**Z-Score Videos**

**Z-Score Videos**