mean

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mean
Message posted by spirit on July 12, 2000 at 12:00 AM (ET)

Rutter Nursery Co.packages department reports that the distribution is normal and the standard deviation of this process is 3 pounds per bag. At the end of each day Jeff Rutter, the production manager, weighs 10 bags from one day's production. Can Mr. Rutter conclude that the mean weight of the bags is different than 50 pounds? Use the .05 significance level.
45.6 47.7 47.6 46.3 46.2 47.4 49.2 55.8 47.5 48.5

I need to see all formulas and work required that involved arriving at an answer, please.

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Re: mean
Message posted by Bill on July 14, 2000 at 12:00 AM (ET)

From you presentation, the population mean (mu=50) and standard deviation (s=3) are known. To compare your sample to the population, use the following: z=(x(bar)-mu)/s/(sqrt(n). For the .05 level, the calculated z value must be > 1.96 (absolute) to reject the null model.

Re: mean
Message posted by Bill on July 14, 2000 at 12:00 AM (ET)

The sigma symbol was displayed in my last post as "s." That is, s=3 is actually sigma=3 and s/sqrt(n) is sigma/sqrt(n).

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