The Normal Distribution is a part of the VCE Further Maths topic Data Analysis and subtopic Investigating Data Distributions. A normal distribution has the same mean, mode and median. The shape of the data is roughly symmetrical and has a graph called a ‘bell curve’. Standard deviation is a measure of how spread out numbers are. The percentage of data that lies within a certain number of deviations is always the same. This is where the ’65-95-99.7′ rule comes in. If a set of data is normally distributed, we know that 68% of the data lies one standard deviation from the mean, 95% lies within the two standard deviations from the mean, and 99.7% lies within the three standard deviations from the mean.
In this post, we look at using ‘the normal model’ for bell-shaped distributions. We also use the 68–95–99.7% rule to estimate percentages and to give meaning to the standard deviation.
What Does it Mean to Be Normally Distributed?
Watch this video to learn about the normal distribution and how to use the 65-95-99.7% rule.
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