Telemarketers generally read from a prepared script when they make

Telemarketers generally read from a prepared script when they make their sales calls. A firm decides to change this prepared script, making it both friendlier and shorter. Daily sales are recorded for a random sample of telemarketers, before and after the script change. The average difference-using a [(before the change) – (after the change)] order of subtraction-is + 4.2, with a sample size of 56. The differences have a standard deviation of 23.4. Do the data suggest that there is a difference in daily sales before and after the script change? Use ? = 0.05. What assumption do you have to make in order to answer this question?

Technically, we assume that we are obtaining simple random samples

Technically, we assume that we are obtaining simple random samples from in?nite populations when obtaining sampling distributions. If the size of the population is ?nite, we technically need a ?nite population correction factor. However, if the sample size is small relative to the size of the population, this factor can be ignored. Explain what an “in?nite population” is. What is the ?nite population correction factor? How small must the sample size be relative to the size of the population so that we can ignore the factor? Finally, explain why the factor can be ignored for such samples.

What is the perfect summer trip? A National Geographic Kids

What is the perfect summer trip? A National Geographic Kids survey (AAA Horizons, April 2007) asked this question to 316 children ages 8 to 14. Their responses are given in the following frequency distribution.,Top Vacation Choice ……………. Frequency,Cruises …………………………… 140,Beaches …………………………… 68,Amusement Parks ………………… 68,Big Cities …………………………. 20,Lakes ………………………………. 12,Summer Camp …………………….. 8,a. Construct a relative frequency distribution. What percentage of the responses cited “Cruises” as the perfect summer trip?,b. Construct a bar chart for these data.