## Experimental Design B/C

dxu46
Exalted Member Posts: 798
Joined: April 11th, 2017, 6:55 pm
Division: C
State: MO

### Experimental Design B/C

Welcome to the 2019 Experimental Design Question Marathon!!!
Question: What is the formula for standard deviation?

Knyte_Xjn
Member Posts: 75
Joined: January 6th, 2017, 8:04 pm
Division: C
State: TX

### Re: Experimental Design B/C

Welcome to the 2019 Experimental Design Question Marathon!!!
Question: What is the formula for standard deviation?
s = sqrt((Σ(y - ȳ)^2)/n-1)
R. I. P. 01/20/2019

dxu46
Exalted Member Posts: 798
Joined: April 11th, 2017, 6:55 pm
Division: C
State: MO

### Re: Experimental Design B/C

Welcome to the 2019 Experimental Design Question Marathon!!!
Question: What is the formula for standard deviation?
s = sqrt((Σ(y - ȳ)^2)/n-1)

UTF-8 U+6211 U+662F
Exalted Member Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

### Re: Experimental Design B/C

Welcome to the 2019 Experimental Design Question Marathon!!!
Question: What is the formula for standard deviation?
To dxu46: Technically, you need to specify whether it's sample standard deviation or population standard deviation because in rare cases you might have the population standard deviation, but maybe that's a little out of the scope of this event . . .
s = sqrt((Σ(y - ȳ)^2)/n-1)
To Knyte_Xjn (and whoever else might be interested in learning how to make mathematics equations look pretty): This paragraph is just a matter of preference and readability. If you don't want to deal with the hassle (which makes sense if you don't write formulae regularly), then you can just ignore this. Anyway, you can use the math tags on this forum to write mathematic formulae. If you don't know the format, I believe it's called , and you should get plenty of results if you just search up "how to write <whatever you want to write> in latex", since it's the standard way to typeset mathematics if you're a scientist or mathematician or whatever. To give an example, your answer would look like
$s = \sqrt{\frac{\sum(y - \bar{y})^2}{n-1}}$
Or, you can use x instead of y: $s = \sqrt{\frac{\sum(x - \bar{x})^2}{n-1}}$
Or, you can write the formula for population standard deviation with a fancy Greek letter: $\sigma = \sqrt{\frac{\sum(x- \bar{x})^2}{n}}$
which I personally think is a lot nicer. Again, no worries if you don't understand what I'm doing here, and if you don't want to spend time figuring it out, don't bother.

dxu46
Exalted Member Posts: 798
Joined: April 11th, 2017, 6:55 pm
Division: C
State: MO

### Re: Experimental Design B/C

Welcome to the 2019 Experimental Design Question Marathon!!!
Question: What is the formula for standard deviation?
To dxu46: Technically, you need to specify whether it's sample standard deviation or population standard deviation because in rare cases you might have the population standard deviation, but maybe that's a little out of the scope of this event . . .
s = sqrt((Σ(y - ȳ)^2)/n-1)
To Knyte_Xjn (and whoever else might be interested in learning how to make mathematics equations look pretty): This paragraph is just a matter of preference and readability. If you don't want to deal with the hassle (which makes sense if you don't write formulae regularly), then you can just ignore this. Anyway, you can use the math tags on this forum to write mathematic formulae. If you don't know the format, I believe it's called , and you should get plenty of results if you just search up "how to write <whatever you want to write> in latex", since it's the standard way to typeset mathematics if you're a scientist or mathematician or whatever. To give an example, your answer would look like
$s = \sqrt{\frac{\sum(y - \bar{y})^2}{n-1}}$
Or, you can use x instead of y: $s = \sqrt{\frac{\sum(x - \bar{x})^2}{n-1}}$
Or, you can write the formula for population standard deviation with a fancy Greek letter: $\sigma = \sqrt{\frac{\sum(x- \bar{x})^2}{n}}$
which I personally think is a lot nicer. Again, no worries if you don't understand what I'm doing here, and if you don't want to spend time figuring it out, don't bother.
a. Yes it's out of the scope for this event
b. Latex looks nicer but takes a bit more work, so why use it when you can communicate the same message in an easier way?

UTF-8 U+6211 U+662F
Exalted Member Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

### Re: Experimental Design B/C

Welcome to the 2019 Experimental Design Question Marathon!!!
Question: What is the formula for standard deviation?
To dxu46: Technically, you need to specify whether it's sample standard deviation or population standard deviation because in rare cases you might have the population standard deviation, but maybe that's a little out of the scope of this event . . .
s = sqrt((Σ(y - ȳ)^2)/n-1)
To Knyte_Xjn (and whoever else might be interested in learning how to make mathematics equations look pretty): This paragraph is just a matter of preference and readability. If you don't want to deal with the hassle (which makes sense if you don't write formulae regularly), then you can just ignore this. Anyway, you can use the math tags on this forum to write mathematic formulae. If you don't know the format, I believe it's called , and you should get plenty of results if you just search up "how to write <whatever you want to write> in latex", since it's the standard way to typeset mathematics if you're a scientist or mathematician or whatever. To give an example, your answer would look like
$s = \sqrt{\frac{\sum(y - \bar{y})^2}{n-1}}$
Or, you can use x instead of y: $s = \sqrt{\frac{\sum(x - \bar{x})^2}{n-1}}$
Or, you can write the formula for population standard deviation with a fancy Greek letter: $\sigma = \sqrt{\frac{\sum(x- \bar{x})^2}{n}}$
which I personally think is a lot nicer. Again, no worries if you don't understand what I'm doing here, and if you don't want to spend time figuring it out, don't bother.
a. Yes it's out of the scope for this event
b. Latex looks nicer but takes a bit more work, so why use it when you can communicate the same message in an easier way?
(a): Yeah I get that, but it's hard not to comment once you've taken a stat course (b): For me honestly, it's around the same amount of work. Also, it's way easier typing \sum than typing an uppercase sigma on most keyboards and operating systems. I think mostly it's a matter of how often you type equations because it becomes second nature quite quickly.

dxu46
Exalted Member Posts: 798
Joined: April 11th, 2017, 6:55 pm
Division: C
State: MO

### Re: Experimental Design B/C

To dxu46: Technically, you need to specify whether it's sample standard deviation or population standard deviation because in rare cases you might have the population standard deviation, but maybe that's a little out of the scope of this event . . .

To Knyte_Xjn (and whoever else might be interested in learning how to make mathematics equations look pretty): This paragraph is just a matter of preference and readability. If you don't want to deal with the hassle (which makes sense if you don't write formulae regularly), then you can just ignore this. Anyway, you can use the math tags on this forum to write mathematic formulae. If you don't know the format, I believe it's called , and you should get plenty of results if you just search up "how to write <whatever you want to write> in latex", since it's the standard way to typeset mathematics if you're a scientist or mathematician or whatever. To give an example, your answer would look like
$s = \sqrt{\frac{\sum(y - \bar{y})^2}{n-1}}$
Or, you can use x instead of y: $s = \sqrt{\frac{\sum(x - \bar{x})^2}{n-1}}$
Or, you can write the formula for population standard deviation with a fancy Greek letter: $\sigma = \sqrt{\frac{\sum(x- \bar{x})^2}{n}}$
which I personally think is a lot nicer. Again, no worries if you don't understand what I'm doing here, and if you don't want to spend time figuring it out, don't bother.
a. Yes it's out of the scope for this event
b. Latex looks nicer but takes a bit more work, so why use it when you can communicate the same message in an easier way?
(a): Yeah I get that, but it's hard not to comment once you've taken a stat course (b): For me honestly, it's around the same amount of work. Also, it's way easier typing \sum than typing an uppercase sigma on most keyboards and operating systems. I think mostly it's a matter of how often you type equations because it becomes second nature quite quickly.
b. Yeah I tend to type the words because I use online graphing utilities (e.g. desmos) and it's easier to type than to click.
Also AOPS Alcumus is easier without latex (primarily because it's too confusing for me)

Knyte_Xjn
Member Posts: 75
Joined: January 6th, 2017, 8:04 pm
Division: C
State: TX

### Re: Experimental Design B/C

Welcome to the 2019 Experimental Design Question Marathon!!!
Question: What is the formula for standard deviation?
s = sqrt((Σ(y - ȳ)^2)/n-1)
Can someone else can ask a question in my place?
R. I. P. 01/20/2019

TheChiScientist
Member Posts: 676
Joined: March 11th, 2018, 11:25 am
State: IL
Location: Suffering in a college class

### Re: Experimental Design B/C

Sure. State the formula for percent error.
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dxu46
Exalted Member Posts: 798
Joined: April 11th, 2017, 6:55 pm
Division: C
State: MO

### Re: Experimental Design B/C

Sure. State the formula for percent error.
the absolute value of the difference between experimental value and accepted value and divide that by accepted value.