A manufacturing company measures the weight of boxes before
shipping them to the customers. If the box weights have a
population mean and standard deviation of 90 kg and 24 kg
respectively, then based on a sample size of 36 boxes, the
probability that the average weight of the boxes will be less than
84 kg is:
0.0668
0.9332
0.0228
0.5312
Suppose you take a sample of size 4 from a population with a
mean of 70 and a standard deviation of 10. Based on such a sample,
what are the mean and standard deviation of the sampling
distribution of the sample mean?
70; 5
17.5; 10
70; 2.5
17.5; 5
Cannot be determined if sample size is not at least 30
Suppose you take a sample of size 4 from a population that is
normally distributed with a mean of 70 and a standard deviation of
10. Based on such a sample, what is the (approximate) probability
of getting a sample mean between 60 and 80?
0.025
0.05
0.5
0.95
0.975
Suppose you take a sample of size 4 from a population that is
normally distributed with a known standard deviation of 10. You get
a sample mean of 20. What is the probability the population
mean is 30 or more?
0.025
0.05
0.5
0.95
Either 0 or 1, but we don't know which.
You want to estimate the proportion of Canadians who have read
fewer than 2 books in the past year. You think the population
proportion is about 0.65. What is the minimum sample size you
need to be able to use a normal approximation in your statistical
analysis?
29
15
16
28