Verified answer

Let x = mean, σ = standard deviation.

Then using 3 sigma rule, outliers would be values that are more than 3σ away from mean

So values < x - 3σ = 90 - 3*5 = 75

or values > x + 3σ = 90 + 3*5 = 105

So any values not within interval [75, 105] is considered an outlier.

Now since I don't have the actual readings, I can't tell which are outliers.

But we can look at the number of expected outliers:

Now percentage of values within 3σ of mean is 99.74%

So percentage of outliers is about 0.16%

0.16% of 200 = 0.0016 * 200 = 0.32

Rounding to nearest number, you would expect NO outliers.

In a sample of 200 measurement, even 1 outlier is 3 times the expected number of outliers.