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MTH 220 May 20 Open Questions
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AvatarGreg Miller
8:04
Yes.. and I no you can't type it.. but technically it's greater than or equal to 6.81.. doesn't change answer... just letting you know.
Kasey
8:04
Im working on my conclusion for the pollution case... in 2A we said the p-value p(t17>6.81) does the greater than sign come from the Ha?
AvatarGreg Miller
Not everyone can come to chat b/c they have work or other committments... so those that read it later... please include your work on tests!   Don't give up partial credit!!
7:54
I should have said "normally don't come to chat".. I know some people don't come to chat but READ it later at night.
7:53
Showing steps is important.. too many people are still leaving too many things out.. not a problem for those I have talked with today.. but across the class.. if others that normally come to chat wander upon this thread later.. please include your work... show what you are doing.. so I can trace.
Kasey
7:51
yes dr. miller I think you will be doing that for my midterm...
AvatarGreg Miller
Those using TI calculators are still getting outright p-values
7:51
Kasey...that is TRUE if you use the t-chart
Kasey
7:50
Just to clarify, now our p values are going to be between numbers and we won't ever have the out right pvalue?
AvatarGreg Miller
7:50
Random Comment for anyone else who reads this thread later:  These questions are why on exams you ALWAYS show all your steps and work.. so that I can catch small mistakes and give due partial credit.
Ben
7:45
It works, I won't forget that one now, Thanks!
cool 1
AvatarGreg Miller
7:43
Hey.. no worries.. that's why  you come check!
Ben
7:43
I don't know why thought that. Glad I got that cleared up, nothing would have worked right if I kept that up.
AvatarGreg Miller
7:42
M = sample median (not needed in t-test)... mu = population mean.. which is parameter in t-test and appears in Ho and in test statistic.
7:41
mu is the value from Ho.. Ho:  mu = 4
7:40
don't need median in t statistic
Ben
7:40
mu(as in median)=3.75          With 16 values i did (3.7+3.8)/2 =median
AvatarGreg Miller
7:40
leads me to t = -3.05
7:39
denominator is .3027 divided by 4 since sqrt(16) = 4
7:38
ok.. so numerator of t is 3.769-4
Ben
7:38
yes, got it
AvatarGreg Miller
7:38
X-bar=3.769.. get that?
7:37
Ahhhh.. I still don't think that's right.. let's keep tracing.. hold on switching back to firefly...
Ben
7:36
Found my issue, I left a value out when I was adding up the X values. Does a t-value of 0.251 seem more reasonable? This results in strongly rejecting the Ha in this case.
AvatarGreg Miller
7:35
Yes.. .that's it.
Kasey
7:35
-3.0017
7:33
lack of sleep!
yawn 1
AvatarGreg Miller
7:33
try again and tell me what you get for t now
Kasey
7:33
wrote the formula down wrong....
AvatarGreg Miller
7:33
yep.. usually something just like that.. just small oversight.
Kasey
7:32
oh! that's it! I didn't square rrot
AvatarGreg Miller
7:31
So, calculate s divided by square root of 10 for denominator
Kasey
7:30
should it be 20-17.17 because that' how I got a negative number
AvatarGreg Miller
so.. numerator is -2.83
7:30
No.. numerator is 17.17 - 20.. negative t statistic is fine..and correct here.
7:29
Yes
Kasey
7:29
20 is mu
AvatarGreg Miller
7:29
All the numbers that go into "t" that is
7:28
So, you got something off when you plugged into "t".. b/c all your numbers are right.
Kasey
7:28
17.17
cool 1
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