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ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Suppose the average is 5 Individual observations, say one of them is 4

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3There are two types of deviations 1) Standard 2) Absolute

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Absolute deviation here \[\text{observation}\text{average or arithmetic mean}\] \[54=1\]

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0Absolute deviation is for a set of data elements, correct?

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2sorry I misspoke earlier. I meant Variance, not arithmetic mean

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3NP:) Standard deviation is the square root of variance

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2how about we establish a more concrete example?

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3@ParthKohli It's for individual element

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2I hope it is not too much to ask

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0But it's for an individual element from a set of elements, correct?

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Consider a population consisting of elements 2, 4, 4, 4, 5, 5, 7, 9 Let's find the mean first \[\frac{2+4+4+4+5+5+7+9}{8}=5\]

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Now, we'll find the difference of each data point from the mean and we'll square it \[(25)^2=9\]\[(45)^2=1\]\[(45)^2=1\]\[(45)^2=1\]\[(55)^2=0\]\[(55)^2=0\]\[(75)^2=4\]\[(95)^2=16\]

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0I think I have seen this on Wikipedia.

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Yes, I have taken the same example

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0So the variance is \(4\).

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Now, we need to find the average of these values That'll be the variance \[\frac{32}{8}=4\]

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Square root of this is standard deviation \[\sqrt 4=2\]

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2why do we square the differences?

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0Yup, can you tell me the formula for variance?

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0@msumner Because we must have a positive value, that's why.

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0Well... something along the lines of the above.

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3To find the absolute value of the difference, yes @ParthKohli is right

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

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0That is why statistics is pretty trivial.

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Yeah, then just take the absolute value of difference

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0Will we get the same answer?

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3We'll get Absolute deviation for individual element

ash2326
 2 years ago
Best 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

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

ash2326
 2 years ago
Best 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

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.03 + 1 + 1 + 1 + 2 + 4 = 12

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Average of the absolute deviation is 12/8=1.5

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2is this the same concept as the distance between points?

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0Wow, I just got enlightenment.

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3@msumner do you get the insight?

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2Yes. How come there are two formulas for Standard Deviation?

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0This is somewhat like that.

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0Absolute deviation and standard deviation are different. T_T

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3That's average absolute deviation, the one we found earlier was standard deviation

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3What do you want to know?

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

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

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2I hope my questions are not a nuisance or troublesome!

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0You think your questions are nuisance? What... no!

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3I think standard deviation will provide a better insight of the variation of the sample,

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

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0I am 13 and I have even more n00bish questions.

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2Here is what I am talking about

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Ok, I never knew this, thanks Let me find about these

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0http://en.wikipedia.org/wiki/Statistical_population and http://en.wikipedia.org/wiki/Statistical_sample

ParthKohli
 2 years ago
Best ResponseYou've already chosen the best response.0It says that a sample is a subset of population.

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3Population 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

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2Hero do you know what ash is talking about?

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

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2@ParthKohli a Sample is said to be taken from a bigger population

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2draw then upload works!

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2now I get it. thank you!

ash2326
 2 years ago
Best ResponseYou've already chosen the best response.3I should close it, shouldn't I?

msumner
 2 years ago
Best ResponseYou've already chosen the best response.2yes, please. Thank you once again
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