Standard deviation: Measures the average amount that items vary (deviate) from the mean of an entire data set.

Same mean and median, but different variability. Example: Data set #1: 40, 70, 100 Mean = Median = Data set #2: 69, 70, 71 Mean = Median = Same mean and median, but different variability. (Diverse data vs. concentrated data.)

Variance: Another statistic used to describe the spread of data about the mean.

To compute the standard deviation of a data set: 1st: subtract the mean from each data point, then square each result. 3rd: apply a square root 2nd: add, then divide the results to get an average measure 4

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Notation you will find in your calculator: *Very important! Notation you will find in your calculator:

down if you did NOT save the helpful hints!! listed on the gold “check answers” & helpful hints handout from two days ago: Please write this down if you did NOT save the helpful hints!!

p. 914 #6 Find the mean deviation and standard deviation. Show work! $4.45, $5.50, $5.50, $6.30, $7.80, $11.00, $12.20, $17.20

When solving for Mean Deviation: Write the calculator command that you are using and fill in the appropriate numbers. newer operating system

See HINT for #17-19 at the bottom of yesterday’s check answer sheet:     OR