Posted by **Alison** on Saturday, December 22, 2012 at 2:38pm.

Let x be a random variable representing the monthly cost of joining a gym. We may assume that x has a normal distribution and that the population standard deviation is $5.20. A fitness magazine advertises that the mean monthly cost of joining a gym is $35. You work for a consumer advocacy group and are asked to test this claim. You find that a random sample of 40 health club monthly costs has a mean of $37.30. If you assume that the population mean is $35, find the standardized sample test statistic.

- Math -
**PsyDAG**, Sunday, December 23, 2012 at 2:31pm
Are you talking about a Z score for the difference between means?

Z = (mean1 - mean2)/standard error (SE) of difference between means

SEdiff = √(SEmean1^2 + SEmean2^2)

SEm = SD/√n

If only one SD is provided, you can use just that to determine SEdiff.

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.

## Answer This Question

## Related Questions

- Math (Statistic) - Considered the sampling distribution of a sample mean ...
- Statistics - The monthly incomes from a random sample of workers in a factory ...
- Math - Random variables X and Y are both normally distributed with mean 100 and ...
- Satistics - Monthly incomes of employees at a particular company have a mean of...
- MATH - Which of the following normal distributions has the smallest spread? A. A...
- Statistics - The following is a histogram (right skewed) of the first ten terms ...
- Statistics - 1. The scores of students on the ACT college entrance examination ...
- statistics - 1.A magazine reported that 6% of Americans read the news paper ...
- Business - For a continuous random variable x, the population mean and the ...
- statistics - A specific study found that the average number of doctor visits per...

More Related Questions