Question

9. According to a study, 16 – 26-year-olds make an average of 6.9 visits to shopping malls per week. A researcher wanted to check if this mean is true for the current population of 16 – 26-year old. A random sample of 45 such persons showed that the mean number of visits to shopping malls was 7.2 per week with a standard deviation of 1.3. Using the 2% significance level, is the mean number of visits to shopping malls per week for the current population of 16 – 26 – year – old is more than 6.9?
Answer:

Answer 1

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.