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MTH 220 May 25 Open Questions
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AvatarGreg Miller
Those are right Ashli.. so what happened with slope calculation then???
8:56
keep going Kasey
Kasey
8:56
OK now I keep getting *-857.1429/square root of 941925.2114
Ashli Owens
8:56
okay, I have Sx 16.49675 and Sy 9.28132
AvatarGreg Miller
8:55
By the way x=50 isn't legal!!
To get the slope estimate you'd need sx and sy... that must be where the mistake it Ashli
Kasey and I have been working thru toward r = -.933
8:54
Sorry... no... you must have an error on sx or sy
Ashli Owens
8:53
Hi Dr. Miller and Kasey! I am looking at what you have been typing, and it looks like that part of my work is good...I got y^ = (17.6974)+(-0.0566)(X) for my formula for least squares regression line....Then for X = 20 I got 16.5089....and for X=50, I got 14.8109... is that part looking right to you?
AvatarGreg Miller
8:49
Yes.. 516..
Kasey
8:49
ok cool beans.
8:48
sorry 516*
AvatarGreg Miller
8:48
I was typing too fast.. you got it
Kasey
you had 517
8:48
is the denominator the square root of 1632.8571*576.8571?  below you have a 1 were I have the 7 and I'm wondering if that was just a miss step
AvatarGreg Miller
8:45
It's downhill once you get "r" and the standard deviations of each sample.. the regression phase calculations are fewer
Kasey
8:44
lol and that was the easier part. lord help me. ok I'm going to keep going.
AvatarGreg Miller
8:43
yes.. THATS the numerator for r
Kasey
8:43
Ok sorry got it now I think the 105 was throwing it way off.  I got -857.1429
AvatarGreg Miller
8:42
yes.. subtract that from 896
Kasey
8:42
test I get 1753.142
AvatarGreg Miller
8:42
divide it by 7
Kasey
8:41
then I take that number which is 12272
AvatarGreg Miller
8:41
yes.. that's the 1753 and some change
Kasey
then divide that by 7
8:40
ok I must be putting something in the calculator wrong. I do 104*118
AvatarGreg Miller
8:39
it's 104
104.. sorry
8:38
I thought you told me total of x is 105
Kasey
8:38
I got 105 for x
AvatarGreg Miller
8:38
896 - 1753.142857
8:37
But, the other totals you gave me were correct
Kasey
Ok I must still have some wrong in my 5 column chart
8:37
I keep getting -874 for the numerator
AvatarGreg Miller
8:37
896 - (104*118)/7
in correlation/regression problems I mean
8:35
yes... n is always the number of PAIRS
Kasey
8:35
n= 7 correct?
AvatarGreg Miller
8:30
Lots to keep up with.. keep working on it tonight.. I want you to get to the regression part too..
Kasey
8:29
ok I also see that I dropped my square root somewhere and didn't rewrite it as I was working the problem.
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