Math geniuses!!! Need help with SD.

[Henry]

Thanks guys! Very sweet of you.

And that's why I love this place (among other reasons).

Y'know when you're a kid and you wanna know something, you ask your dad?

Now that I'm all growed up, I come here.

Thanks again!

Love,
Snoweel

You're welcome.


Now, brush your teeth and clean up your room! It's a mess!

 

[Fast Learner]

Let's say a PC with STR 10 is using a nonmagical greatsword. When he hits, the average damage result would be 7. Now, what is the standard deviation?

It doesn't work that way. Standard deviation is used to help explain the results from an existing set of numbers. It's not used to determine odds of success or failure.

I you had a set of completed die rolls, you could calculate the mean and standard deviation of the completed rolls.

 

[dinsdale]

It doesn't work that way. Standard deviation is used to help explain the results from an existing set of numbers. It's not used to determine odds of success or failure.

I you had a set of completed die rolls, you could calculate the mean and standard deviation of the completed rolls.

Well kind of...

If you assume the dice are "fair", then you CAN calculate the EXPECTED Standard Deviation, which in this case is 2.45

A real set of data from perfectly fair die rolls should approach this standard deviation (in the limit of infinite rolls).

 

[Kyramus]

I am going to assume you meant the LSAT.
The highest LSAT score you can obtain is 180. Hence your 160 marks as an 88.8889% of the overall test.

151.88 with a sd of 9.57 could have a range of 142.31-161.45.

SO using this possibility, you are 99.101889% of the 15 people that took the test. with probably 1 person higher than you by a few points.

you did good overall.

Congratulations.

 

[jgbrowning]

The reason is that I just received my result from my Law School Entrance Test and have less of a clue than I did before I opened the letter.

Now, the test consisted of a total of 70 questions, each of equal value. Of that I'm sure.

How'd I really do?

Welcome to Law!


joe b.

 

[ichabod]

Well, what you do is you calculate your z-score. Subtract the mean from your score and divide by the standard deviation. In your case that's .8589. Now you look that up on a table of the standard normal distribution, and with a little interpolation you get that 80.48% scored worse than you. Now, that assumes that scores are normally distributed and the numbers given were the true mean and standard deviation. My guess is that their close enough that 80% is a good estimate.

 

[tarchon]

It doesn't work that way. Standard deviation is used to help explain the results from an existing set of numbers. It's not used to determine odds of success or failure.

I you had a set of completed die rolls, you could calculate the mean and standard deviation of the completed rolls.

No, SD can be calculated for a probability distribution just as well as for measurements. I can't really blame you for thinking that though, since a lot of people do come out of elementary stats classes thinking the same thing.
The SD for the greatsword case is ~2.415 if you ignore crits. With a crit roll added in, it will be roughly 1.4 times that, but I didn't bother to compute it exactly.

 

[bob_the_bard]

Are you thinking about law school in Sweden? I go here in the states, whats it like in Sweden?