Question

Ms. Johnson uses a statistics program to analyze all the data collected by her students during a lab experiment about acceleration due to gravity. The program reports =31.5 and .

What is the variance of the data? Round to the nearest tenth.

1.6
2.5
5.6
6.3
The graph shows the distribution of hand lengths, in centimeters, of the members of an orchestra.

A graph shows the horizontal axis numbered 14 to x. The vertical axis is unnumbered. The graph shows an upward trend from 14 to 19 then a downward trend from 19 to 24.
What is the variance of the data?

1
2
4
5
The dot plot represents the amount of rain recorded by rain gauges in different locations around a city.

A number line going from 0.25 to 2.75. 0 dots are above 0.25. 3 dots are above 0.5. 1 dot is above 0.75. 3 dots are above 1. 0 dots are above 1.25. 1 dot is above 1.5. 2 dots are above 1.75. 3 dots are above 2. 2 dots are above 2.25. 1 dot is above 2.5. 0 dots are above 2.75.

How many rain gauges recorded rainfall?

2
8
11
16

Answer 1

1) 6.3
Explanation: variance = (standard deviation)^2 = 2.5^2 = 6.25 ≈ 6.3.

2) 4
Explanation: the distribution is symmetric about 19 with frequencies 1,2,3,4,5,4,3,2,1 (for values 15–23). Mean = 19. Compute population variance = [0·5 + 1·8 + 4·6 + 9·4 + 16·2] / 25 = 100/25 = 4.

3) 16
Explanation: total dots = 3+1+3+1+2+3+2+1 = 16.