Question

the class boundaries should have been: 7.15, 8.45, 9.75, 11.05, 12.35, 13.65. these class boundaries are used as dividers for the bars on the histogram. each class boundary is represented on the horizontal axis below. at the center of each interval is a point represented by a large black dot. drag the five dots to the correct heights for the bars of the histogram. note: if any frequency is zero (0), drag its bar up a bit, then back down to zero so that the value is registered.

Explanation:

Step1: Understand the Task

We need to set the height of each dot (representing the center of each interval) based on the frequency. The note says if frequency is 0, drag up then down to 0.

Step2: Analyze Each Interval

Looking at the given frequencies (all 0 as per the dots' labels), so for each dot (at 7.15, 8.45, 9.75, 11.05, 12.35 centers), we follow the note: drag up a bit then back to 0. So the height of each dot remains at 0 (after the drag - up - then - down action to register the 0 frequency).

Answer:

Each of the five dots (at the centers of the intervals with boundaries 7.15, 8.45, 9.75, 11.05, 12.35) should be set to a height of 0 (after performing the drag - up - then - down action for 0 - frequency intervals as per the note).