Organizing Data

Warm-up Can you come up with a data set with a median of 7, and mean of 8, and modes of 4 and 7?

Surveyed a class of 16 How many cars does your family own? # cars 0 1 2 3 4 5 6 # students 2 4 5 2 1 1 1 How could we quickly display this information?

Create a line plot! X X X X X X X X X X X X X X 0 1 2 3 4 5 6 Find the mean, median, and mode number of cars. mode = 2 median = 2 mean = 2.1875 Why is the mean higher than the median?

Or a histogram!

Scores on a pop quiz 17, 52, 61, 63, 66, 70, 72, 73, 78, 81, 84, 85, 88, 89, 92, 93 Why might a line plot not be especially useful? Let’s try a histogram with intervals. Can you find the mean, median and mode from the histogram? Would you expect the mean to be higher or lower than the median? Are there any scores that are “official” outliers?

Now let’s try a stem-and-leaf plot! Can you name one or two benefits over a histogram? Easy to make, does not lose actual data.