Help with Calculation

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NumeracyIlliterate

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Hello Guys and Gals

New member here so please be gentle :)

I have a question if someone would be so kind.

I am currently a studying a basic statistical analysis unit at University as part of my IT degree and am having massive dramas with probabilties formulas.

I am slowly understanding the formulas and why they are used in certain scenarios - ie: to get Z values and T values etc etc.

Now I understand that this is going to sound like a really dumb question and for that I apologize, but when I attended school which was many years ago I did advanced math and all without a calculator - who would have thought!

My question is: How do I enter massive calculations into a statistical calculator (and I'm truly hoping someone can break it down for me):

eg: How would I enter .70 - .60 divided by the square root of .60(1-.60) divided by 50

Any help with this would be truly appreciated because now that I have a reasonable understanding of the how and why it is simply driving me nuts that I keep coming up with incorrect answers all because I can't figure out how to enter it in a statistical calculator which I have never used before.

My calculator model is a SHARP EL738F by the way and if it helps you assist me.

Cheers folks - really appreciate any assistance you may be able to offer
 
NumeracyIlliterate said:
Hello Guys and Gals

New member here so please be gentle :)

I have a question if someone would be so kind.

I am currently a studying a basic statistical analysis unit at University as part of my IT degree and am having massive dramas with probabilties formulas.

I am slowly understanding the formulas and why they are used in certain scenarios - ie: to get Z values and T values etc etc.

Now I understand that this is going to sound like a really dumb question and for that I apologize, but when I attended school which was many years ago I did advanced math and all without a calculator - who would have thought!

My question is: How do I enter massive calculations into a statistical calculator (and I'm truly hoping someone can break it down for me):

eg: How would I enter .70 - .60 divided by the square root of .60(1-.60) divided by 50

Any help with this would be truly appreciated because now that I have a reasonable understanding of the how and why it is simply driving me nuts that I keep coming up with incorrect answers all because I can't figure out how to enter it in a statistical calculator which I have never used before.

My calculator model is a SHARP EL738F by the way and if it helps you assist me.

Cheers folks - really appreciate any assistance you may be able to offer
Click to expand...
(.70)*(.60)/sqrt(60*(1-.60))/50
 
Jomo said:
(.70)*(.60)/sqrt(60*(1-.60))/50
Click to expand...

Unfortunately not - typing it in exactly as you have specified gives an answer of: 0.017146428 with 9 DP set.

Edit: typing it in exactly as you have specified (except I put (.70)*(.60)/sqrt(.60*(1-.60))/50 as the question specifies

The answer required though (and given in the example I am studying) is 1.44

Any other ideas?
 
Last edited:
NumeracyIlliterate said:
eg: How would I enter .70 - .60 divided by the square root of .60(1-.60) divided by 50
Click to expand...

You're missing grouping symbols.

It's going to be the meaning of one of the following.

It will either be

(.70 - .60) divided by the (square root of .60(1-.60)) divided by 50

or it will be this

(.70 - .60) divided by the square root of (.60(1-.60) divided by 50). \(\displaystyle \ \ \ \ \ \) <----- This will get you the 1.44 rounded value. **


For this type of statistics problem, the difference, (.70 - .60), gets the
main fraction bar directly underneath it, regardless.


The first meaning is \(\displaystyle \ \ \ \dfrac{.70 \ - \ .60}{ \ \ \dfrac{\sqrt{.60(1 \ - \ .60)} \ }{50} \ \ }.\)



The second meaning is \(\displaystyle \ \ \ \dfrac{.70 \ - \ .60}{ \ \ \sqrt{\dfrac{.60(1 \ - \ .60) \ }{50}} \ \ }. \ \ \ \ \ \) ** See above.
 
Last edited:
lookagain said:
(.70 - .60) divided by the square root of (.60(1-.60) divided by 50). \(\displaystyle \ \ \ \ \ \) <----- This will get you the 1.44 rounded value. **
Click to expand...

This is exactly what I was looking for and rounded is perfect as in this case I am determining Sampling distribution of the Proportion - thank you so much for your help.

To ask another question (maybe I should save this for another thread?) - is there an easy way to determine how to split up a complicated calculation such as I have asked about and make it understandable how to enter it in the calculator. I don't want to make errors which could obviously be otherwise avoided (and lose marks in an Exam) if there was a "formula" of sorts I could follow to enter in the parameters?

Hope this makes sense.

lookagain - ty so much again - you are awesome!
 
Last edited:
Denis said:
There are many ways! An example:
a = .70 - .60
b = SQRT[.60*(1 - .60) / 50]
a / b will = 1.4433...

It is extremely important to "isolate" numerators and denominators.
40 / 2 * 5 = 20 * 5 = 100
but:
40 / (2 * 5) = 40 / 10 = 4
Get my drift?

Suggest you go here:
http://www.khanacademy.org/math/alg...rations/v/introduction-to-order-of-operations

Listen carefully and you'll come back an expert:rolleyes:

And remember the 3 rules:
1: practice
2: practice
3: practice
Click to expand...
Denis, where were you when I needed these rules. I studied, studied and when I was done studying I studied more. And look where that got me.
 
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