ROIs and statistics

[MiniN]

hi, i'm going for a job interview in a few days and as part of that I need to do a maths test as part of the interview process. i'm not brill at maths and have found out the maths Q's will probably relate to statistics, spercifically ROI's and percentages.

can anyone tell me about ROI's, what they are and how you 'do' tham and any tricks for working out percentages?

also are there any other math things that relate to statistics?

please help

[dancecaller]

Could ROI stand for rates of interest? If so they are percentages, and the same principles apply.
If they ask how much interest at, say 7%, on capital of �1,200
7% is �7 for every �100 (or 7p for every100p)
So find out how many hundred �s
1,200 didvided by 100 is 12
There are 12 (hundred pounds) and you get �7 for every hundred pounds.
So you get 7 multiplied by 12 pounds
�84

What is 5% of 660
Divide by 100 and multiply by 5 (or multiply by 5 and divdie by 100, you get the same answer)
660/100=6.6
6.6*5=33
OR 660*5=3300
3300/100=33

Going the other way round
If there are 35 children in the class and 7 have red hair what % have red hair?
Turn this into a fraction 7/35. Cancel and get 1/5.
One fifth have red hair so 100/5 out of every hundred have red hair or 20%

It's hard to explain in words. Check your answer by thinking if its the right size. 7 in 35 as a percent will be bigger than 7 but smaller than 100.

If you also have a written test don't forget to check your work. As a practise you could look for the spelling mistakes, capital letters missing and a phrase repeated in your question above. (I find it harder to write sense on a keyboard than in handwritting, do you?)

[dancecaller]

http://www.mathsisfun.com/percentage.html
http://mathforum.org/library/drmath/sets/selec t/dm_percentage.html
These explain percentage. And this gives examples for you to practise
http://www.mathgoodies.com/lessons/vol4/meanin g_percent.html
This one gives statistics lessons
http://www.aaaknow.com/sta.htm#topic1

[MiniN]

thanks for your help.

yeah it is hard making sense on a keyboard and easier through writing.

thanks for maths tips. hopefully i wont flunk the test!

if you think of anymore tips, let me know as i'm quite rusty at maths.

[MiniN]

thanks for the links. it feels like homework being back at school! haha

[ewand]

Here's some tips I gave to a similar question a while back.......you should be able to find some stuff on the internet either through google or wiki. Hope this is useful:

http://www.theanswerbank.co.uk/Society-and-Cul ture/People-and-Places/Question83243.html

[MiniN]

Many thanks
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