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Intro into Standard Deviation and practice questions.
What is standard deviation?
A summary measure of the differences of each observation from the mean.
What is normal distribution referred to as?
A bell-shaped curve.
What does standard deviation measure?
The speed or variation in a bell-shaped curve (normal distribution).
About what percentage of data should be ONE standard deviation above and below the mean?
68%
About what percentage of the data should be TWO standard deviation above and below the mean?
95%
About what percentage of the data should be THREE standard deviation above and below the mean?
99%
In statistics, how is the mean represented?
x̄
What will standard deviation vary depending on?
Standard deviation will vary depending on the data that you collect.
According to the graph, which data set has a smaller standard deviation?
A
According to the graph, which data set has a higher standard deviation?
B, because it is more spread out.
What does each element represent in the standard deviation formula?
s = Standard deviation
n = The total number of data points
n - 1 = Degrees of freedom
x̄ = Mean
Σ = Sum
What is standard error?
The standard error of a statistic is the standard deviation of its sampling distribution.
What does each element represent in the standard error formula?
SE = Standard error
x̄ = Mean
s = Standard deviation
n = The total number of data points
Note 
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