For a standard normal curve, find the z-score that separates the bottom 70 from the top 30.
A) 0.12 B) 0.98 C) 0.47 D) 0.53
Q. 2Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. A vending machine will only accept coins weighing between 5.48 g and 5.82 g. What percentage of legal quarters will be rejected?
A) 2.48 B) 1.96 C) 0.0196 D) 1.62
Q. 3For a standard normal curve, find the z-score that separates the bottom 30 from the top 70.
A) -0.12 B) -0.53 C) -0.98 D) -0.47
Q. 4The lengths of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. What is the probability that a pregnancy lasts at least 300 days?
A) 0.0179 B) 0.9834 C) 0.4834 D) 0.0166
Q. 5For a standard normal curve, find the z-score that separates the bottom 90 from the top 10.
A) 2.81 B) 1.28 C) 1.52 D) 0.28
Q. 6A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. If an applicant is randomly selected, find the probability of a rating that is between 170 and 220.
A) 0.3811 B) 0.0703 C) 0.1554 D) 0.2257
Q. 7Can money buy happiness? A researcher wanted to determine whether there was any association between economic status and happiness. She selected a sample of 1000 adults and interviewed them.
Each person was asked about their financial situation and their level of happiness was evaluated. The researcher analyzed the results to determine whether there was an association between economic status and happiness.
A) cohort; Individuals are observed over a long period of time.
B) cross-sectional; Information is collected at a specific point in time.
C) retrospective; Individuals are asked to look back in time.
Q. 8Vitamin D is important for the metabolism of calcium and exposure to sunshine is an important source of vitamin D. A researcher wanted to determine whether osteoperosis was associated with a lack of exposure to sunshine.
He selected a sample of 250 women with osteoperosis and an equal number of women without osteoperosis. The two groups were matched - in other words they were similar in terms of age, diet, occupation, and exercise levels. Histories on exposure to sunshine over the previous twenty years were obtained for all women. The total number of hours that each woman had been exposed to sunshine in the previous twenty years was estimated. The amount of exposure to sunshine was compared for the two groups.
A) retrospective; Individuals are asked to look back in time
B) cohort; Individuals are observed over a long period of time.
C) cross-sectional; Information is collected at a specific point in time.