which formula?` (1 Viewer)

[kayles]

im unsure when to use the present value formula or the future value formula and ive tried doing examples to help me but i still dont understnad...
please help me....

 

[lil_lainy]

well, when they tell you that u need to have a certain, amount, say $2000, in like 20 yrs, they will ask u how much u need to put in 2 satrt with, or sumthing, then u use the present value formula.

and when they say that sumbody invests $400 a motnth, how much will they have in 20 yrs, u use future value

u probably already no that and like that was no help at all but anyway, i tried...nobody else answerd

good luck

 

[sez809]

I'd like to help you but I have no idea, I hate loans, annuities, interest etc!! Do you know which standard deviation to use - sample or population? WB ASAP!!

 

[_random_]

yep! im in the same boat, someone help, quick!

 

[kayles]

thanks heaps dude... that helps...

 

[lil_lainy]

alrite with th stanadra deviation

when they give u the marks from the results of a WHOLE class, and ask you to find the sd, u use the population one

but when they say like 5 students were chosen from a class and their reults taken, then u use the sample

if u get a question in the exma just like c if it is talking about a WHOLE group or just a part of one, and then use the popuation or sample accordingly

hope i have bin of sum help

good luck

 

[glitterfairy]

Here you go dear hearts!

This is glitterfairy's not-at-all-foolproof way of deciding which formulae to use. It makes me smile though.

When in doubt, and if you have time, do both formulae and you'll see which one is more relevant. Otherwise, just follow my "What the hell..." method

Best wishes!

PS:

Ok, my attachment isn't working. I am pissed off. Ok, let me write it for you...

PRESENT
x ----------> ?
"How the hell am I going to end up?!?!?!"


FUTURE
? <---------- x
"How the hell did I get here?!?!?!"

Nice and simple...