Statistic Exercise

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brockjames4

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I am in a statistics class at the University of Phoenix. I have really been struggling with it and it is the final week of the course and am lost on 2 statistics exercises need to be completed by Monday Sept 27th. It is Thursday Sept 23rd today and I would greatly appreciate any help to solve the 2 exercise statistic problems below. If someone does have time to to solve these 2 exercise problems by Monday Sept 27th I would be very grateful for you help. If you could show each step used to solve them also I would appreciate that as well. Thank you very much in advance for all the help and time anyone spent to help me with this!


8.46 A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were

3.87 131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477

(a)Construct a 90 percent confidence interval for the true mean weight.
(b) What sample size would be necessary to estimate the true weight with an error of } 0.03 grams with 90 percent confidence?
(c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during manufacture.
(Data are from a project by MBA student Henry Scussel.)
 
First, I'm a little puzzled by the results of your very accurate scale. One might expect the same number of significant digits. Those first two are a bit odd.

Second, just do it.

a) Compute the mean
b) Compute the sample standard deviation for a sample of size 10.
c) Find the appropriate t-score for a sample of size 10.
d) You're almost done with (a)

For (b), take a look at part (a). How wide is that interval? I'm guessing it's more that 0.06. Now you need to decide what changes the width of the interval.

Take one more sample, 11. What is the t-score for that? Is the interval 0.06 yet?
Take one more sample, 12. What is the t-score for that? Is the interval 0.06 yet?
etc...

For (c) - What do you think? It's a thought question. Feel free to do some thinking. Don't forget the possibility that the wrapping machine may go crazy and use two papers every once in a while. Humidity? What? Search your brain.
 
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