Author Question: The incomes of trainees at a local mill are normally distributed with a mean of 1,100 and a standard ... (Read 17 times)

codyclark · **on:** Jul 25, 2018

The incomes of trainees at a local mill are normally distributed with a mean of 1,100 and a standard deviation 150. What percentage of trainees earn less than 900 a month?

A) 90.82 B) 35.31 C) 9.18 D) 40.82

Question 2

Researchers wanted to determine whether there was an association between city driving and stomach ulcers. They selected a sample of 900 young adults and followed them for a twenty-year period.

At the start of the study none of the participants was suffering from a stomach ulcer. Each person kept track of the number of hours per week they spent driving in city traffic. At the end of the study each participant underwent tests to determine whether they were suffering from a stomach ulcer. The researchers analyzed the results to determine whether there was an association between city driving and stomach ulcers.
A) cohort; Individuals are observed over a long period of time.
B) retrospective; Individuals are asked to look back in time.
C) cross-sectional; Information is collected at a specific point in time.