The tread life of a particular brand of tire is a random variable best described by a normal distribution with a mean of 60,000 miles and a standard deviation of 1500 miles.
What is the probability a certain tire of this brand will last between 56,850 miles and 57,300 miles?
A) 0.4920 B) 0.4649 C) 0.9813 D) 0.0180
Q. 2A survey found that 33 of 66 randomly selected women and 37 of 66 randomly selected men follow a regular exercise program.
Find a 95 confidence interval for the difference between the proportions of women and men who follow a regular exercise program.
A) -0.231 to 0.109 B) 0.330 to 0.670 C) 0.298 to 0.702 D) -0.263 to 0.702
Q. 3A student wished to use a table of areas for the standard normal curve to find the z-score having an area to its right of 0.52. The student started by looking for the closest area to 0.
52 in the body of the table and reading off the corresponding z-score which was 0.05. She then subtracted this z-score from 1 to get 0.95. Was her reasoning correct? If not, where did she go wrong and how would you have solved the problem?
Q. 4256 people were asked if they were satisfied with their jobs. 45 said that they were. H0: p = 0.36.
A) 4.125 B) 0.188 C) 2.612 D) 3.000
Q. 5Find the z-score for the value 93, when the mean is 92 and the standard deviation is 2.
A) z = 0.99 B) z = -0.99 C) z = 0.00 D) z = 0.50
Q. 6Out of 200 observations, 64 were successes. H0: p = 0.49.
A) 4.243 B) 1.723 C) 1.291 D) 0.005
Q. 7The area under the standard normal curve to the right of a z-score is 0.56. Explain how you could use a table of areas to find the z-score.
What will be an ideal response?
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