Question

criteek is a website where fans of horror films go to write movie reviews. on the websites home page there is a display of the number of movies reviewed by a selection of the sites top critics. the histogram below summarizes the data. use the histogram to answer each of the questions.
(a) how many critics have from 15 to 22 movie reviews?
(b) what is the class width?
(c) how many critics have 23 or more movie reviews?

Explanation:

Part (a)

Step1: Identify the bar for 15 - 22

Look at the histogram, the bar for "15 to 22" has a frequency (y - axis) of 6.

Step2: Confirm the value

The height of the bar corresponding to 15 - 22 movie reviews is 6, so the number of critics is 6.

Step1: Choose a class interval

Take the first class interval: 7 to 14.

Step2: Calculate the width

Subtract the lower limit from the upper limit: \(14 - 7=7\). Check with another interval, e.g., 15 - 22: \(22 - 15 = 7\). So the class width is 8? Wait, wait, 15 - 7 = 8? Wait, no, 14 - 7+1? No, in histograms, class width is upper - lower. Wait 15 - 7 = 8? Wait 7 to 14: 14 - 7 = 7? Wait no, 15 - 7 = 8? Wait the intervals are 7 - 14, 15 - 22, 23 - 30, 31 - 38, 39 - 46. Let's calculate the difference between the start of consecutive intervals. 15 - 7 = 8? Wait 15 - 7 = 8, 23 - 15 = 8, 31 - 23 = 8, 39 - 31 = 8. Oh right, the class width is the difference between the lower limits of consecutive classes. So 15 - 7 = 8. So class width is 8.

Step2: Verify with interval

Take the interval 7 - 14, upper limit 14, lower limit 7, 14 - 7+1? No, in histograms, class width is usually calculated as upper boundary - lower boundary. But here, the classes are 7 - 14, 15 - 22, etc. So the width is 15 - 7 = 8 (since 14 and 15 are consecutive, so the class width is 8).

Step1: Identify the relevant classes

The classes with 23 or more movie reviews are 23 - 30, 31 - 38, 39 - 46.

Step2: Find their frequencies

For 23 - 30: frequency is 4; for 31 - 38: frequency is 8; for 39 - 46: frequency is 5.

Step3: Sum the frequencies

Add them up: \(4 + 8+5 = 17\).

Answer:

6

Part (b)