Maths Skills

Question 1

How would you lay out the working to work out standard deviation?

Answer 1

Graph with 3 columns.
1 = each value. At the bottom have the total of all these values in the data set.
2 = each value minus the Mean. (Have the mean if all the values at the bottom)
3 = (each value minus the mean) squared. Do this for all of them. Then total them up.
Once you have the total of all these, put them into the formula so you are left with the square root of that total divided by the number of all of the values.

Question 2

How to calculate the IQR

Answer 2

UQ - LQ
Lower quartile = (n+1) / 4 and then find where that value is in the data set.
Upper quartile = 3 lots of (n+1) /4 (3 lots of the last answer to n+1 /4) and then find where that value is in the data set. (Where it would fall. E.g the 9.75th value, would be between the 9th and 10th value.)