Math 50 ā Section #3.4 Name ____________________

Histograms

Professor Jason Wang

1. A statistics teacher surveys some of the students in his statistics classes about

the number of hours they work per week and their responses are described in the

histogram below. Use this information to answer each of the following questions.

Use appropriate units when necessary and write your answer in complete

sentences.

(a) What variable is described by the histogram? Is it discrete or continuous?

(b) How many of the students work between 9 and 25 hours per week?

(c) How many of the students work at least 20 hours per week?

(d) What proportion of the students work less than 10 hours per week?

- For each of the following histograms, describe the shape of each distribution.
- The number of hours that some trigonometry students spent studying for their

first test are described by the density histogram below.

Use the information to answer each of the following questions.

(a) Compute the area of each of the

six bars in the density histogram.

(b) Find the total area of the six bars

(c) Explain why the total area of the bars of any density histogram is always

equal to the result you found in part (b).