Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing

This Question is Closed

ash2326Best ResponseYou've already chosen the best response.3
Suppose the average is 5 Individual observations, say one of them is 4
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
There are two types of deviations 1) Standard 2) Absolute
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Absolute deviation here \[\text{observation}\text{average or arithmetic mean}\] \[54=1\]
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
Absolute deviation is for a set of data elements, correct?
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
sorry I misspoke earlier. I meant Variance, not arithmetic mean
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
NP:) Standard deviation is the square root of variance
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
how about we establish a more concrete example?
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
@ParthKohli It's for individual element
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
I hope it is not too much to ask
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
But it's for an individual element from a set of elements, correct?
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Consider a population consisting of elements 2, 4, 4, 4, 5, 5, 7, 9 Let's find the mean first \[\frac{2+4+4+4+5+5+7+9}{8}=5\]
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Now, we'll find the difference of each data point from the mean and we'll square it \[(25)^2=9\]\[(45)^2=1\]\[(45)^2=1\]\[(45)^2=1\]\[(55)^2=0\]\[(55)^2=0\]\[(75)^2=4\]\[(95)^2=16\]
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
I think I have seen this on Wikipedia.
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Yes, I have taken the same example
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
So the variance is \(4\).
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Now, we need to find the average of these values That'll be the variance \[\frac{32}{8}=4\]
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Square root of this is standard deviation \[\sqrt 4=2\]
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
why do we square the differences?
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
Yup, can you tell me the formula for variance?
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
@msumner Because we must have a positive value, that's why.
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
Well... something along the lines of the above.
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
To find the absolute value of the difference, yes @ParthKohli is right
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
if the goal is to get an absolute value, why not just obtain the absolute value from the get go?
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
That is why statistics is pretty trivial.
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Yeah, then just take the absolute value of difference
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
Will we get the same answer?
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
We'll get Absolute deviation for individual element
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
(2−5)=3 (4−5)=1 (4−5)=1 (4−5)=1 (5−5)=0 (5−5)=0 (7−5)=2 (9−5)=4
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
I doubt we will get the same result consistently if we obtain the absolute value of the difference
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
@ParthKohli No, we won't get the same result Absolute deviation is defined for individual element, we won't take mean in this case
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
3 + 1 + 1 + 1 + 2 + 4 = 12
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Average of the absolute deviation is 12/8=1.5
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
is this the same concept as the distance between points?
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
Wow, I just got enlightenment.
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
@msumner do you get the insight?
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
Yes. How come there are two formulas for Standard Deviation?
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
This is somewhat like that.
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
Absolute deviation and standard deviation are different. T_T
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
That's average absolute deviation, the one we found earlier was standard deviation
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
What do you want to know?
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
why use a different formula when the population or set of elements are larger
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
I misspoke again. why use a different formula when the Sample is taken from a larger population?
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
I hope my questions are not a nuisance or troublesome!
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
You think your questions are nuisance? What... no!
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
I think standard deviation will provide a better insight of the variation of the sample,
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
I just turned 14 so bear with my amateur math questions :(
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
I am 13 and I have even more n00bish questions.
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
Here is what I am talking about
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Ok, I never knew this, thanks Let me find about these
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
http://en.wikipedia.org/wiki/Statistical_population and http://en.wikipedia.org/wiki/Statistical_sample
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
It says that a sample is a subset of population.
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
Population is used when we have data for all the population if we have data only for a sample of population, we use the sample standard deviation to guess estimate for the whole population
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
Hero do you know what ash is talking about?
 one year ago

ParthKohliBest ResponseYou've already chosen the best response.0
The population is the whole thing, and the sample is just the data collected from a small part of it.
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
@ParthKohli a Sample is said to be taken from a bigger population
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
draw then upload works!
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
now I get it. thank you!
 one year ago

ash2326Best ResponseYou've already chosen the best response.3
I should close it, shouldn't I?
 one year ago

msumnerBest ResponseYou've already chosen the best response.2
yes, please. Thank you once again
 one year ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.