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Normal distribution

Normal distribution

From the course: Test Prep: GRE

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Normal distribution

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- [Voiceover] Easiest way I have to talk about the normal distribution of the variable is to illustrate the concept with a Bell curve. So let's say that a teacher gave a test and I'm gonna show the results on a curve. So let's say the mean or the average score was an 80. Then we have 85, 90 and we have 75 and 70. So this is useful to kind of look at what percentage of the data falls within a certain part of the curve. And it's a nice visual because the fatter the part of the curve, the more data is in there. So these lines are going to represent one standard deviation. So between 80 and 85, 85 is one standard deviation above the mean. Then 75 is one standard deviation below the mean. So about 34% of our data is within one above the mean in about 34%, here is one below the mean. Then two standard deviations above the mean is two 90 and two below is the 70. About 14 of our data is here between one and two standard deviations above. Then I get again about 14% of our data is here. So add…

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