Question # 3
Given a standard normal distribution, find the following probabilities: (6 points each)
a. P(z < 1.15)
b. P(z > 0.45)
c. P(-1.9 < z < 0.4)
Question # 4
A study shows that scores on an aptitude test are normally distributed with a mean of 70 and a standard deviation of 12. Find the following probabilities: (6 Points each)
a. If one test taker is selected, that the person scored greater than 75.
b. If 9 test takers are selected, that they have a mean score greater than 75. c. If 49 test takers are selected, that they have a mean score greater than 75.
Question # 5
Use the normal distribution to approximate the following probability: According to the most recent Davenport student profile, 47% of students have children under 17 living at home with them. Find the probability that a random sample of 800 students will return more than 50% students with children under 17 living at home with them. (10 points)
Question # 6
Use Minitab to compute the following two-sided confidence intervals: (6 Points each)
For parts e & f, use the approximate method
a. 95% Confidence Level, Sample Mean = 95, σ (sigma) = 10, and n = 25 b. 95% Confidence Level, Sample Mean = 22, s= 4, and n = 16
c. 95% Confidence Level, Sample Proportion = 0.40, n = 200