Quick Maths (Stats) Help

[sarutobi]

Ok I have a statistics exam tomorrow and im looking over my mock paper and solutions. From the solutions I get this :

I cannot for the life of me figure out where the "+1" and the "15" have come from in those calculations.

 

[JIM_BOB7813]

If you want the Median (middle?) position in a range you add 1 then halve it. Median between 1 and 5 is (5+1 / 2) = 3.

I'm not too sure about the 15. It might be the range between 31-45 (inclusive) of weekly hours which is where the median lies.

 

[Drawoh Tesremos]

The 15 is because the width of the band 31-45 is 15.
You've calculated in (6226.5-5532)/5682 what fraction up that band you want to go, and then multiplying by 15 gives the actual distance up that band you need to be.

 

[sarutobi]

thanks guys