Question 1105643
Mean is 57.8
the variance is the sum of squares of the differences divided by 4, calling this a sample and not a population
-6.8^2+-4.8^2+2.2^2+11.2^2-1.8^2=202.8/4=50.7; sd is sqrt of that.
Reasons why this sd might not be a good estimate:
1. Small sample size
2. Youth (likely), with different memory.
3. Students, so those without same education may not be the same.