A sample of size n=10n=10 is drawn from a population. The data is shown below.
79.8 | 80.2 | 115 | 115 | 103.7 |
90.4 | 115 | 98 | 95.2 | 87.6 |
What is the range of this data set?
range =
What is the standard deviation of this data set? (Remember, it is a
sample.) Please report the answer with appropriate rounding,
reporting 2 more decimal places than the original data. Please,
please, please do not calculate the value by hand.
stdev =
Solution:
The formula for range and standard deviation are given as below:
Range = Maximum – Minimum
Maximum = 115
Minimum = 79.8
Range = 115 – 79.8
Range = 35.2
Standard deviation = Sqrt[∑(X - mean)^2/(n – 1)]
The calculation table is given as below:
No. |
X |
(X - mean)^2 |
1 |
79.8 |
330.8761 |
2 |
80.2 |
316.4841 |
3 |
115 |
289.3401 |
4 |
115 |
289.3401 |
5 |
103.7 |
32.6041 |
6 |
90.4 |
57.6081 |
7 |
115 |
289.3401 |
8 |
98 |
0.0001 |
9 |
95.2 |
7.7841 |
10 |
87.6 |
107.9521 |
Total |
979.9 |
1721.329 |
Standard deviation = Sqrt[1721.329/(10 – 1)]
Standard deviation = Sqrt(191.2587778)
Standard deviation = 13.82963404
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