1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Statistics - Describing distribution curve? - Easy solve

  1. Dec 9, 2009 #1
    This should be a very easy problem, i just can't seem to find what makes the center, shape and spread.

    The distribution of actual weights of 8-ounce chocolate bars produced by a certain machine is normal with mean 8.1 ounces and standard deviation 0.1 ounces. Company managers do not want the weight of a chocolate bar to fall below 7.85 ounces, for fear that consumers will complain.

    Four candy bars are selected at random and their mean weight, x-bar, is computed.
    Describe the center, shape, and spread of the sampling distribution of x-bar.

    My method:

    Mean of x-bar = Mean
    So, the mean of x-bar = 8.1 ounces

    Standard Deviation of x-bar = (standard deviation)/sqrt(n)
    So, 0.1/sqrt(4) = 0.1/2 = 1/20

    Okay, now the distribution curve for x-bar is going to have the characteristics of mean = 8.1 and standard deviation = 0.05. I've gotten that far, but now i don't know how to describe the center (I'm assuming this is 8.1?), shape, and spread or the distribution curve?

    Any help?
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted