As in Session 2, we can determine cumulative frequencies for intervals of data. For example, the number of responses that are less than 60 is the cumulative frequency of 60. (Note that "below 60" means "in the 50s and below.")
If you begin with the stem and leaf plot for the 52 estimates of a minute, the 22 values in the lighter color are the estimates below 60:
The corresponding 22 dots are shown in the dot version of this stem and leaf plot:
And finally, the corresponding bars in the frequency histogram are shown in red:
These three representations tell us that there are 22 estimates below 60.