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GE122 -- Final Examination, (Past Exam) 18. In order to construct a confidence i

ID: 3352746 • Letter: G

Question

GE122 -- Final Examination, (Past Exam) 18. In order to construct a confidence interval estimate of the population proportion p, the value of p is needed. (1) True A randomly selected sample of 100 students had an average grade point average (GPA) of 3.2 witha standard deviation of 0.2. (1) 0.020 (2) 0.200 A random sample of 30 airline flights during a storm had a mean delay of 40 minutes. The standard deviation was 5 minutes. during a storm. (1) (38.2, 41.8) (2) False 19. An approximate value for the standard error of the sample mean is (3) 1.600 (4) 2.000 20. Calculate a 90% confidence interval for the average delay for all flights (3) (31.5, 48.5) (4) (30.4, 45.1) (2) (38.5, 41.5) 21. If z is a standard normal random variable, the area between 0.0 and 1.50 compared to the area between 1.5 and 3.0 will be (3) smaller

Explanation / Answer

Solution18:

to find confidence interval for population nproportion we need sample proportion p^=x/n

but not population proportion ,p.

cconfidence interval for population proportion ,p is

p^+-sqrt(p^(1-p^)/n)

FALSE

Soluition19:

stanadard error of the mean=std dev/sqrt(sample size)

=0.2/sqrt(100)

=0.2/10

=0.02

OPTION(1)