Statistics Notes AII. 11
Heights:
Mean of data
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Mode of data
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Median of data
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Paul Sturgess walks in the room. He is the tallest member of the Harlem Globetrotters at 7ft. 8 inches. How is his height going to influence the mean, median, and mode?
Mean of data
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Mode of data
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Median of data
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If one of Mrs. Luckett’s 34 inch tall nieces comes in this class, how will her height influence the measures?
Mean of data
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Mode of data
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Median of data
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Mean, Median, and Mode are central tendencies. Unlike these, the Standard Deviation of the data is used to describe the span of the data. Let’s look at your height data.
Standard Deviation
A statistic that tells us:
How far from ___________________ a certain piece of data is.
How _____________ _________________ the data items are in our data set.
The mathematic symbol for standard deviation is the lower case Greek letter _____________ and it looks like this:
Calculating Standard Deviation
Data Set = {600, 470, 170, 430, 300}
Step 1: Calculate the ____________ .
m = _____________ mm.
Step 2: Calculate the _________________ from the mean for each element (xi) in the data set.
Step 3: ______________ each difference from Step 2.
Step 2 Step 3
600 - m = ______________ ______________
470 - m = ______________ ______________
170 - m = ______________ ______________
430 - m = ______________ ______________
300 - m = ______________ ______________
Step 4: Find the mean m (average) of the numbers in Step 3.
We call this number the ________________ and is represented by the math symbol σ2
Step 5: The standard deviation is the ________________ ______________ of the variance. s = _________________
Normal Distribution- Has data that vary randomly from the mean. The graph of a normal distribution is called the Normal Curve.
The mean, median, and mode are equal
The normal curve is bell shaped and symmetric about the mean
The total area under the curve is equal to one
The normal curve approaches but never touches the x-axis as it extends from the mean
Contains inflection points at µ - σ and µ + σ, where the curve changes from curving upward to downward. (µ is the mean)(σ is the standard deviation)
The mean gives the location of the line of symmetry and the standard deviation describes how much the data are spread out.
A standard normal distribution has a mean of 0 and a standard deviation of 1. It also has an area under the curve of 1.
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