Question

The electronic sign that showed the speed of motorists was installed on a road.the line plots below show the speeds of some motorists before and after the sign was installed. based on these data which statement is true about the speeds of motorists after the sign was installed?

Answer 1

The correct option is;

A. The mean speed and the range of the speeds of the motorists decreased

Explanation:

Here we have the speeds given as

Before Sign Installation

Speed Frequency

20 1

24 1

25 4

30 2

35 2

38 1

40 1

∑ 212 12

Mean = 17.67

Median (25 + 30)/2 = 27.5

Range = 40 - 20 = 20

After Sign Installation

Speed Frequency

20 1

22 1

25 4

28 1

30 3

35 2

∑ 160 12

Mean = 160/12 = 13.33

Median = (25+28)/2 = 26.5

Range = 35 - 20 = 15.

Therefore, the mean speed and the range of the speeds of the motorists decreased