Using it's concept, the standard deviation of the data is of 3.742.
<h3>What are the mean and the standard deviation of a data-set?</h3>
- The mean of a data-set is given by the <u>sum of all values in the data-set, divided by the number of values</u>.
- The standard deviation of a data-set is given by the square root of the <u>sum of the differences squared between each observation and the mean, divided by the number of values</u>.
For this data-set, the mean is:
M = (1 + 4 + 4 + 4 + 4 + 6 + 5)/7 = 4.
Hence the standard deviation is:

More can be learned about the standard deviation of a data-set at brainly.com/question/12180602
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Answer:
Step-by-step explanation:
Let x be the original number.
x - 15 - 1/2(x - 15) - 10 = 12
x - 15 - 1/2 x + 7.5 - 10 = 12
1/2x - 25 + 7.5 = 12
1/2x - 17.5 = 12
1/2x = 27.5
x = 55
If you do 0.2 x 40, you get 8. So, 0.2% of 40 is equal to 8.