Homework: You should do problems 1 & 2 over the weekend. You
might sit down with a friend and both go thru problem 4 (the computer
assignment). We will cover the information for doing problem 3 on
Monday (and part d of 2.70 on Monday).
Stem & leaf (used on homework).
Histogram = summary of data with a graph
Statistics = summary of data with a number
Examples of statistics
mean = average
variance = average squared deviation
standard deviation = squareroot of variance
median = middle of data
Range = top - bottom (a bad statistic)
IQR = top 25% - bottom 25%
The key advantage of a statistic is that you can present many of them all at once
(Think about drawing 10 histograms. It generates a very cluttered picture.)
Box plots--a compromise between statistics and graphics