Normal Distributions

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Transcript Normal Distributions

Normal Distributions
A.K.A. – THE BELL CURVE
Before we talk about normal distribution….
Let’s refresh our memory on measures of center.
Measures of center are mean, median and mode.
The mean is the average. We find the mean by finding the sum of the data
set and dividing the sum by the number of data pieces. We use the greek
symbol µ to note the mean.
The median is the middle data value of the data set when it is listed in order
from least to greatest.
The mode is the data value that appears most often.
Examples:
Is there an outlier in either of the examples above? If so, which measure
of center would be most affected by it?
Standard Deviation
The standard deviation refers to the spread of the data and how far typical
data points vary from the mean value.
The symbol for standard deviation is σ.
Normal Curve
Example:
Example:
Skewedness
Examples: