What is the standard deviation of the following data set rounded to the nearest tenth 3,17,18,15,12,21,9a.4.1b.4.0c.3.8d. 3.7

Hey,
To find the Standard deviation of the data set, there are 4 steps:
1. Work out the Mean (the simple average of the numbers)
2. Then for each number: subtract the Mean and square the result.
3. Then work out the mean of those squared differences.
4. Take the square root of that and we are done!

Here is your
6.1

Is there a typo? I have checked my answer multiple times. Perhaps are you missing a number in the data set?

Cheers,
Izzy