Standardised Values is a part of the VCE Further Maths topic Data Analysis and subtopic Investigating Data Distributions. A z-score is a statistical measure of how many standard deviations a raw score is above or below a mean. They are used to compare scores that are in a normal distribution. For instance, a z-score of 0 means it is equal to the mean, a z-score of 1 means its one standard deviation above the mean and a z-score of -1 means it is 1 standard deviation below the mean. The higher or lower the z-score, the further it is from the mean.
It is difficult to compare two different sets of data on two different graphs. For instance, how do we compare a student’s mark in English with their math mark? Thankfully, z-scores can help us compare scores from different data, making the comparisons easier.
In this post, we look at standardised values and their use in comparing data values across distributions.
Z-Scores and Distributions
In this video, we look at what a z-score is and how it is applied to the normal distribution.
This next video looks at how to find a z-score.
How Do You Convert Z-Scores into Actual Scores?
This video will teach you about finding the actual score when given the z-score.
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