Answer
See below
Work Step by Step
The mean, median, mode, range, and standard deviation of the data set when the outlier is included:
$\bar x=\frac{20+20+25+25+28+28+100}{7}=35.14\\ Median =25\\Mode =24.3\\Range=80\\\sigma =\sqrt \frac{(20-35.14)^2+(20-35.14)^2+(25-35.14)^2+(25-35.14)^2+(28-35.14)^2+(28-35.14)^2+(100-35.14)^2}{7}=26.65$
The mean, median, mode, range, and standard deviation of the data set when the outlier is not included:
$\bar x=\frac{20+20+25+25+28+28}{6}=24.33\\ Median =25\\Range=8\\\sigma =\sqrt \frac{(20-24.33)^2+(20-24.33)^2+(25-24.33)^2+(25-24.33)^2+(28-24.33)^2+(28-24.33)^2}{6}=10.89$
