Mean is adding all the numbers then dividing the answer you go from the numbers.
Using it's concept, the standard deviation for the given data-set is of 8.22.
<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>.
The mean for this problem is:
M = (17 + 26 + 28 + 9 + 30 + 29 + 6 + 21 + 23)/9 = 21
Hence the standard deviation is:

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No, the given sequence is not an arithmetic sequence.
What is Arithmetic Sequence ?
An arithmetic sequence is a list of numbers with a definite pattern. If you take any number in the sequence then subtract it by the previous one, and the result is always the same or constant then it is an arithmetic sequence.
In the above question,
The sequence is 3,5/2,3/2,-3/2,...
Take the 2nd term and minus the 1st term.
Now take the 3rd term and minus the 2nd term.
We can clearly notice that the differences are not same. Hence there is no common difference and therefore it's not an arithmetic sequence
To read about arithmetic sequence click here :
brainly.com/question/27079755
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