Practice English Speaking&Listening with: Theoretical Normal Distribution - Intro to Descriptive Statistics

For the most part, we're going to focus on normally distributed data. There are

many kinds of normal distributions. Stretched, skinny, or maybe somewhere in the

middle. But the area underneath will always be 1, or 100%. You've also seen

before that in a normally distributed data set, the mean, median, and mode are

approximately equal. In our theoretical model, they're exactly equal. Our

theoretical model is perfectly symmetrical. This doesn't usually happen in real

life. These models approximate our real distributions. But we can usually get

pretty good approximations. And in our theoretical model, most of the data is in

the middle clustered around the mean, median and mode. You might recall from the

last lesson that approximately 68% lie within one standard deviation of the

mean. And 95% fall within 2 standard deviations of the mean.