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rjceynar
Group Title
For a group of 22 college football players, the mean heart rate after a morning workout session was 88 beats per minute with a standard deviation of 5. Find the 95% confidence interval of the true mean for all college football players after a workout session.
 2 years ago
 2 years ago
rjceynar Group Title
For a group of 22 college football players, the mean heart rate after a morning workout session was 88 beats per minute with a standard deviation of 5. Find the 95% confidence interval of the true mean for all college football players after a workout session.
 2 years ago
 2 years ago

This Question is Open

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
Statistics right?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
I can help.
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
So have you covered the t distribution yet?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
I'm willing to work through it to show you how to do this problem. If you haven't covered the tdistribution. Then Just use this formula:
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
dw:1354857899830:dw
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
dw:1354857941165:dw
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
Thanks so much for the help. Im guessing thats a sqrt(n) on the bottom?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
Does this make sense so far?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
dw:1354858016253:dw
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
Now, in class do you use a graphic calculator or table?
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
Both. :/ But I prefer the calculator.
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
Following so far?
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
I think so..
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
Because its a 95% confidence interval, wouldnt it include all values withen 2 standard deviations of the mean?
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
If so, how does that come into play? or am i trialing off??
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
dw:1354858281536:dw
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
Right, so we need to know the total area under that portion of the curve, right?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
So basically, you're looking for the area under the curve right up to one of horizontal lined regions.
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
And the lines are 2 std deviations from the mean, right?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
I'll return to that later. So, for now, what is the area where the horizontal lines are?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
dw:1354858667169:dw
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
So the horizontal lines add up to .05. So x+x=.05 That means x=.025. That is the area under one of the horizontal striped .
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
dw:1354858861005:dw
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
that means the area under the curve up to that point is 10.025 = 0.975
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
Following so far
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
That will a be the p value that you can enter into the calculator. so invnorm(0.975)
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
it will be close to 2, but not exactly 2.
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
what result do you get for the z score?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
You still there?
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
You should get something like 1.96 for the z value
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
basically ,that's the reason why 95% of the population is around 2 standard deviations from the mean.
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
Ah. Makes sense now.
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
The invnorm() command converts a cumulative probability to a zscore
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
It's important to calculate the z scores right or these type of problems will be difficult.
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
Do you think you can finish from here?
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
I can try. :) Thanks so much for the help.
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
Use this formula and the values that I just solved for:
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
dw:1354859367648:dw
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
z=1.96, s=5, n=22
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
Awesome. Only thing really left to do now is plug in and apply. Thanks so much.
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
Let me know what you get....
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
so dw:1354859570561:dw
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
88+1.96(5/22) 881.96(5/22) right? so 88.44 and 87.55 ??
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
2.09 is the margin error
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
85.9 to 90.1
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
it's sqrt 22
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
ah.... caught me
 2 years ago

zordoloom Group TitleBest ResponseYou've already chosen the best response.1
Is that it?
 2 years ago

rjceynar Group TitleBest ResponseYou've already chosen the best response.0
thats it. :) Thanks
 2 years ago
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