The heights in cm, of 10 children are 145, 163, 159, 162, 167, 149, 150, 160, 170, and 155. The standard deviation of the heights of the children is
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Correct Answer: Option E
Explanation:
Let's calculate the standard deviation.
1. Calculate the Mean:
The mean height is:
\[
\text{Mean} = \frac{145 + 163 + 159 + 162 + 167 + 149 + 150 + 160 + 170 + 155}{10} = \frac{1,580}{10} = 158
\]
2. Calculate Each Squared Difference from the Mean:
\[
(145 - 158)^2 = (-13)^2 = 169
\]
\[
(163 - 158)^2 = 5^2 = 25
\]
\[
(159 - 158)^2 = 1^2 = 1
\]
\[
(162 - 158)^2 = 4^2 = 16
\]
\[
(167 - 158)^2 = 9^2 = 81
\]
\[
(149 - 158)^2 = (-9)^2 = 81
\]
\[
(150 - 158)^2 = (-8)^2 = 64
\]
\[
(160 - 158)^2 = 2^2 = 4
\]
\[
(170 - 158)^2 = 12^2 = 144
\]
\[
(155 - 158)^2 = (-3)^2 = 9
\]
Sum of squared differences:
\[
169 + 25 + 1 + 16 + 81 + 81 + 64 + 4 + 144 + 9 = 594
\]
Calculate the Variance:
\[
\text{Variance} = \frac{504}{10} = 59.4
\]
Calculate the Standard Deviation:
\[
\text{Standard Deviation} = \sqrt{59.4} \approx 7.7
\]
The corrected standard deviation of the heights is approximately 7.7cm.
Let's calculate the standard deviation.
1. Calculate the Mean:
The mean height is:
\[
\text{Mean} = \frac{145 + 163 + 159 + 162 + 167 + 149 + 150 + 160 + 170 + 155}{10} = \frac{1,580}{10} = 158
\]
2. Calculate Each Squared Difference from the Mean:
\[
(145 - 158)^2 = (-13)^2 = 169
\]
\[
(163 - 158)^2 = 5^2 = 25
\]
\[
(159 - 158)^2 = 1^2 = 1
\]
\[
(162 - 158)^2 = 4^2 = 16
\]
\[
(167 - 158)^2 = 9^2 = 81
\]
\[
(149 - 158)^2 = (-9)^2 = 81
\]
\[
(150 - 158)^2 = (-8)^2 = 64
\]
\[
(160 - 158)^2 = 2^2 = 4
\]
\[
(170 - 158)^2 = 12^2 = 144
\]
\[
(155 - 158)^2 = (-3)^2 = 9
\]
Sum of squared differences:
\[
169 + 25 + 1 + 16 + 81 + 81 + 64 + 4 + 144 + 9 = 594
\]
Calculate the Variance:
\[
\text{Variance} = \frac{504}{10} = 59.4
\]
Calculate the Standard Deviation:
\[
\text{Standard Deviation} = \sqrt{59.4} \approx 7.7
\]
The corrected standard deviation of the heights is approximately 7.7cm.