Stati sti cs - Portage Online Summer
Module 5 Exam
Exam Page 1
Suppose that you take a sample of size 18 from a population that is not normally distributed. Can
the sampling distribution of xx be approximated by a normal probability distribution?
No, the sampling distribution of xbar cannot be approximated by a normal probability distribution
because the population is "not normally" distributed and the sample size is less than 30.
Answer Key
Suppose that you take a sample of size 18 from a population that is not normally distributed. Can
the sampling distribution of xx be approximated by a normal probability distribution?
No. The population is not normally distributed, therefore, we need a sample size of at least 30 to
approximate by a normal probability distribution.
Exam Page 2
Suppose that you are attempting to estimate the annual income of 1100 families. In order to use the
infinite standard deviation formula, what sample size, n, should you use?
(n / N ) ≤0.05
N = 1100
n ≤ (0.05 x 1100 ) = 55
n ≤ 55
The sample size (n) has to be less than or equal to 55
Answer Key
Suppose that you are attempting to estimate the annual income of 1100 families. In order to use the
infinite standard deviation formula, what sample size, n, should you use?
Module 5 Exam
Exam Page 1
Suppose that you take a sample of size 18 from a population that is not normally distributed. Can
the sampling distribution of xx be approximated by a normal probability distribution?
No, the sampling distribution of xbar cannot be approximated by a normal probability distribution
because the population is "not normally" distributed and the sample size is less than 30.
Answer Key
Suppose that you take a sample of size 18 from a population that is not normally distributed. Can
the sampling distribution of xx be approximated by a normal probability distribution?
No. The population is not normally distributed, therefore, we need a sample size of at least 30 to
approximate by a normal probability distribution.
Exam Page 2
Suppose that you are attempting to estimate the annual income of 1100 families. In order to use the
infinite standard deviation formula, what sample size, n, should you use?
(n / N ) ≤0.05
N = 1100
n ≤ (0.05 x 1100 ) = 55
n ≤ 55
The sample size (n) has to be less than or equal to 55
Answer Key
Suppose that you are attempting to estimate the annual income of 1100 families. In order to use the
infinite standard deviation formula, what sample size, n, should you use?
