1=.99999999999 I hate math, especially Statistics right now and I need help

Baywillow

Alright, using the following sample of 4 observations: 3, 5, 5, 8

Calculate the sample variance (accurate to two decimal places)
I got 3.19 by:
1) Getting the range, which was: 5
2) Getting the average which was: 5.25
3) Getting the square of all the oberservations subtracted by the mean and then adding them together to get: 12.75
4) I then subtracted the range 5, by 1: to get 4
5) Finally I divided 12.75/4 to get 3.19 (rounded)

It was wrong; the choices are: a) 1.79 b) 2.06 c) 3.19 d) 4.25

I also need to calculate the sample standard deviation, and I got 1.79 by just taking the square root of 3.19 from before. It was also wrong; again the choices are: a) 1.79 b) 2.06 c) 3.19 d) 4.25

And then also theres this stem and leaft plot diagram I don't understand; say 2|7= 27.000000

well:

0|12334456667
1|0012459
2|7
3|7

I have to find the range: and I got 36 from that by doing 37-1, but that too was wrong; the choices are 3, 35.9, 36.9, 37, and none of the above; I chose 35.9;

Further more I have to calculate the IQR. First I got 10 by subtracted the first quartile (4) from the 3rd quartile (14), but that was wrong.

And stupid question probably, but how many variables does a histogram have, if y = frequency and x = x; I thought it migth be 2.

Baywillow

Ok I'm assuming 4.25 was the sample variance since if you take the square root of 4.25 you get 2.06, and 2.06 being the standard deviation. But how to get 4.25 in the first place? Where did I go wrong?

I also hate biology. I'm mainly just attending college to learn how to dig for artifacts.

Motorhead

Originally posted by Baywillow


I'm mainly just attending college to learn how to dig for artifacts.

 

Come over to my house.  I'll teach you how to do it for a lot cheaper, and maybe I'll finally get that lime tree planted....

layzwombat

Well.... I would talk to your prof...  2.06 is the Std Dev. making 4.25 the variance (apparently I'm an idiot) I guess it has to do with weather it is a sample or a population (weather the denominator is n-1 or just n) I'm used to sigma squared - which is actually 3.19.  picky professor... if he didn't mention anything in class about this before.



I believe you are correct about the second question. - but I was wrong before



The histogram question doesn't have a correct answer as it is stated.  A histogram can show freq and number, but it can also show location and other things (multiple y or multiple x axis) - I guess my answer would have to be 3....

mithrandir72

Originally posted by Vendayn

Here, I can teach you with these easy steps



1. Grab a shovel

2. Go to the artifact site, start digging until you see the artifact(be careful not to destroy the artifact with the shovel of doom)

3. Grab a paintbrush or some kind of small soft brush...brush the dirt off.

4. Grab a secure box, put artifact in box, make sure artifact is secure as not to break it

5. Keep the artifact or sell it for millions of dollars

5. Congragulations, you completed 5 easy steps to digging for artifacts.



Nah, j/k man :P Its probably more complicated than that

Yeah, to get to the really good artifacts, you have to use explosives. Unfortunately, you usually never know if you've found something good.

Mylon

Um, as far as I know, archaeologists don't really do the digging.  They just get basic labor to do that.  The archaeologists really do the interpretive work of what they find to determine what the objects were used for, how the people lived, and so on.

modjoe86

Use the Data Analysis toolpak in Excel. It does all that work for you.



As for the histogram: It depends on your regression. Simple Regression is two variables, multiple regression is 3+.

Mylon

Originally posted by modjoe86

Use the Data Analysis toolpak in Excel. It does all that work for you.



As for the histogram: It depends on your regression. Simple Regression is two variables, multiple regression is 3+.

It's important that one knows how to do these calculations manually.  Unfortunately, Excel is usually not a tool available during tests.

modjoe86

Originally posted by Mylon

Originally posted by modjoe86

Use the Data Analysis toolpak in Excel. It does all that work for you.



As for the histogram: It depends on your regression. Simple Regression is two variables, multiple regression is 3+.

It's important that one knows how to do these calculations manually.  Unfortunately, Excel is usually not a tool available during tests. I'm in my thrid data class right now, and I've always been given the regression output on tests. Data analysis is more about interpreting results than knowing how to calculate them. Then again it could be different for other universities.