To help study neighborhood demographics, a community organization conducts a survey of 10 neighborhood residents, asking each one how many children under 18 live in their household. The responses are given below.

1, 3, 1, 0, 2, 0, 0, 2, 0, 0

What are the mean and standard deviation of this data set?
Mean: 0.50, Standard Deviation: 2.00
Mean: 0.90, Standard Deviation: 1.10
Mean: 1.10, Standard Deviation: 0.90
Mean: 1.50, Standard Deviation: 3.00
Mean: 0.90, Standard Deviation: 1.21

1 answer

To calculate the mean and standard deviation of the given data set, follow these steps:

1. Add up all the values:
1 + 3 + 1 + 0 + 2 + 0 + 0 + 2 + 0 + 0 = 9

2. Divide the sum by the number of values to find the mean:
Mean = 9 / 10 = 0.9

3. Calculate the squared differences between each value and the mean:
(1-0.9)^2 = 0.01
(3-0.9)^2 = 4.41
(1-0.9)^2 = 0.01
(0-0.9)^2 = 0.81
(2-0.9)^2 = 1.21
(0-0.9)^2 = 0.81
(0-0.9)^2 = 0.81
(2-0.9)^2 = 1.21
(0-0.9)^2 = 0.81
(0-0.9)^2 = 0.81

4. Find the variance by summing up all the squared differences and dividing by the number of values:
Variance = (0.01 + 4.41 + 0.01 + 0.81 + 1.21 + 0.81 + 0.81 + 1.21 + 0.81 + 0.81) / 10 = 0.90

5. Calculate the square root of the variance to find the standard deviation:
Standard Deviation = sqrt(0.90) = 0.95

Therefore, the correct answer is:
Mean: 0.90
Standard Deviation: 0.95