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Thread: Statistics Help - Sorry I just cant figure this out at all

  1. #1
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    Statistics Help - Sorry I just cant figure this out at all

    For 1996, the us department of agriculture estimated that american consumers would have eaten on average 2.6 pounds of cottage chesse throughout the course of that year. based on a longitudinal study of 98 randomly selected people conducted during 1996 the national center for cotage chesse studies found an average cottage cheese consumption of 2.75 pounds and a standard deviation od s=14 ounces. Given this information which of the following statements would be correct concerning a twotail test at the .05 level of significance?

    A. we can conclude that the average cottage cheese consumption in America isn't 2.6 pounds per person per year
    B. we can conclude that the average cottage cheese consumption in America is at least 0.705 pounds more or less than 2.75 pounds per person
    C. we can conclude that we can't reject the claim that the average cottage cheese consumption in America is 2.6 pounds per person per year
    D. we can conclude that the average cottage chesse consumption in America is actually 2.75 pounds per person per year.
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  2. #2
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    Re: Statistics Help - Sorry I just cant figure this out at all

    C

    Edit: By the way, I just eyeballed it and guessed an answer. I'd recommend giving us a little more information. What have you tried? Why are you having trouble with this problem? Your title says you just can't figure this out at all. What is it that you do not understand? Is it the set-up? Do you not understand the two-tailed test? Does this link help?

    https://en.wikipedia.org/wiki/One-_and_two-tailed_tests
    Last edited by SlipEternal; Jun 28th 2017 at 04:53 PM.
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  3. #3
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    Re: Statistics Help - Sorry I just cant figure this out at all

    So I am in distance learning so I don't actually have a professor teaching me statistics. For some reason all this is just gone over my head. I am not understanding how to set up a problem to solve it. And when I do try something its no where near the answer. I don't understand the one tail nor two tail test. I checked out the link but I am still confused. I actually have couple other problems that I am having issues with as well. Like with p-values I don't understand those either, nor do I understand the whole type 1 and type 2 errors. And the rejection region. I don't even want answers if someone could just help explain it in maybe a way my book can't. I have been trying to look at different things on internet to get some help as well.
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  4. #4
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    Re: Statistics Help - Sorry I just cant figure this out at all

    Statistics are only as good as the sample that generates them. Statisticians understand this, and they attempt to use statistics they believe to be good to determine the relevance of a suspect statistic. So, you have a study using an unknown methodology yielding an average amount of cottage cheese consumed. Where did that number come from? After all, 86% of all statistics are made up on the spot! So, the statistician runs his own test. He gathers a sample of 98 individuals and calculates some statistical data about their cottage cheese consumption habits. You are even told that this is a longitudinal study. 98 is a large enough number of people that it should give a fairly reliable statistics. So, they find that 2.75 pounds (2 pounds 12 ounces) of cottage cheese was consumed on average by their sample, but there was a fairly wide distribution of cottage cheese consumption. The standard deviation was 14 ounces (that is just shy of one pound). Now, the 5% confidence interval means that there is 2.5% on either tail of bell curve. That means, with 95% confidence, you can assert that any statistic that is more than 2 standard deviations from the mean is a bad statistic. It can be rejected with a fairly high level of confidence. Two standard deviations from the mean would be anything less than 1 pound or anything more than 4 pounds 8 ounces would be a bad statistic. 2.6 pounds is actually in the range of "I don't know whether the statistic is good or bad". It is less than the average given by the longitudinal study, certainly. But, not enough less that we can discredit it completely.

    As for the rest of your questions, I would need more information on what specifically confuses you. I do not have time to write a statistics book, nor would I be qualified to do so.
    Last edited by SlipEternal; Jun 28th 2017 at 05:53 PM.
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