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Compare the following heights in inches:. Computational Formulas and IQR’s. Computational Formula:. This is an easier computational formula that contains no rounding. Let’s try it!. You try one!. Is the standard deviation affected by outliers?.
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Computational Formula: This is an easier computational formula that contains no rounding.
The following data represents the heights of some students in my class. • Find the mean & st. dev. • What % are within 1 st. dev. Of the mean? • What % are within 2 st. dev. Of the mean?
IQR – Interquartile Range • This is the measure of variability that is not affected by outliers. • It’s based on quartiles.
25% 25% 25% 25% - This is the median of the lower ½ of the sample. - This is the median. - This is the median of the upper ½ of the sample.
If normal distribution – then you can estimate the standard deviation with the IQR. Standard Deviation *Can also be use to check to see if a distribution is normal – if much larger then it’s skewed.
Homework • Worksheet • Use the new formula to compute the standard deviation.