Brothers! I need maths help!

[Llama]

Okay, I have a question about standard deviation. Well, sort of.

As far as my understanding goes, Standard Deviation (SD for short) is a measure of how spread data is from the mean of that data.

1) Is that right?

In this context, I have a group of results. The people have been asked to guess the correct size of an angle (It's 44). How, the results of these people are in a grouped frequency table. So, my questions are:

2) Can I use the actual angle size instead of the mean result, to get the SD from the actual size? (If that makes sense)

3) How do I do this using a grouped frequency table of results?

Help would be appreciated, i'm a bit of a Maths noob

Cheers, Llama

 

[Beerdude26]

Yeah, you really need to pay attention to those things, because you'll easily mix them up. I spent two hours just learning the difference between all the deviations and differences for my exam

Unfortunately, I also promptly forgot/confused them afterwards, so I am unable to help you.

 

[Llama]

Okay, as far as I know, standard deviation for a grouped frequency table is the square root of


? f (x – actual value)^2
--------------------------------
?f

(f is the frequency.)
? = That weird sign that means 'the total of' (Sigma, I think?)

Firstly, is that equation correct?
Secondly, In what order do I tackle the operations at the top?

Aargh, my head hurts.

 

[Beerdude26]

Oh, you'll start crying when you have to learn about Z-values.

 

[Llama]

*dickslaps Beerdude* SHUTUP SHUTUP SHUTUP!

I'm a wee 15 year old, don't scare me with that sorta stuff

 

[Llama]

apologies for the double post. Update: I've now found the SD of two sets of data - One is 7.47, one is 14.59.

Does that mean the set with the lower SD is more precise than the other? If not, what does it mean?

 

[AKIRA]

oh god data management..how i wish i paid attention to you in grade 12

 

[Jintor]

Grade 12? I did this last year.

(Although I forgot it the day after exams, so whatever. )

 

[Stigmata]

Data Management was Discrete Math Lite.

That being said, I didn't do particularly well in Discrete Math.

 

[Krynn72]

I did pretty well in all my math classes, but I could never remember what the names of things were. I have no idea what "Standard Deviation" means.

 

[Ennui]

I can't remember most of the specifics of my Statistics classes, only stuff like z-tests and t-tests and whatnot.

 

[jverne]

I hate statistics! i had a professor who would mentally rape you on the exam.

sorry i could help you a bit, but i'm to lazy to find my stat book, or try to remember it. :cheese:

 

[Kyorisu]

You are just going to love calculus.

 

[AKIRA]

Grade 12? I did this last year.

(Although I forgot it the day after exams, so whatever. )

lol wut?


what grade were you in last year? Because i was in grade 12..i r confused

 

[Kyorisu]

Don't you guys have some weird start end dates? Ours are a tad different, heres SAs 2007 dates for example.

1st Term - 29 January – 13 April
2nd Term - 30 April - 6 July

Semester 1 end.

3rd Term - 23 July - 28 September
4th Term - 15 October - 14 December

Semester 2 end.

Depending on your year level you'll switch subjects between semesters. University dates differ quite a lot from these ones btw.

 

[Jintor]

lol wut?


what grade were you in last year? Because i was in grade 12..i r confused

10.

Grade10charlol.