Here is the histogram of the distribution for systolic readings of blood pressure.

1. How many classes are here?
2. Estimate a range of a data.
3. Find the bin width (a width of a class).
4. Estimate the range of a class where the median lies.
5. Do you expect the mean to be greater or less than the median. Explain your answer.
6. Estimate the proportion of systolic measurements below 100.