Question

5) For a sample of size $n = 20$, and $\alpha = 0.05$, $t_{\alpha/2, n-1}$ can be found from the table to be: (1) A. 2.093 B. 2.086 C. 1.729 D. 1.725 E. None of the above 6) A 95% confidence interval for the population mean is calculated to be 75.29 to 81.45. If the confidence level is reduced to 90%, the confidence interval will: (1) A. Remain the same B. Become wider C. Double in size D. Become narrower E. Most likely no longer include the true value of the population mean 7) Given that the variance equals to 4, and $z_{\alpha/2} = 1.96$ if the Confidence interval length should be at most 1.2, what is the required sample size? (1) A. 42 B. 43 C. 10 D. 11 E. 7 8) A coin is tossed three times. What is the probability that it lands on head exactly one time: (2) A. 0.375 B. 0.125 C. 0.250 D. 0.333 E. 0.500 9) Consider discrete random variable X, with the distribution function given in the table below, the expected value is: (2) A. 1.0 B. 2.0 C. 5.0 D. 0.5 E. 0.4 x | 0 1 2 3 4 f(x) | 1 2 4 2 1

          5) For a sample of size $n = 20$, and $\alpha = 0.05$, $t_{\alpha/2, n-1}$ can be found from the table to be:
(1)
A. 2.093
B. 2.086
C. 1.729
D. 1.725
E. None of the above
6) A 95% confidence interval for the population mean is calculated to be 75.29 to
81.45. If the confidence level is reduced to 90%, the confidence interval will:
(1)
A. Remain the same
B. Become wider
C. Double in size
D. Become narrower
E. Most likely no longer include the true value of the population mean
7) Given that the variance equals to 4, and $z_{\alpha/2} = 1.96$ if the Confidence interval
length should be at most 1.2, what is the required sample size?
(1)
A. 42
B. 43
C. 10
D. 11
E. 7
8) A coin is tossed three times. What is the probability that it lands on head exactly
one time: (2)
A. 0.375
B. 0.125
C. 0.250
D. 0.333
E. 0.500
9) Consider discrete random variable X, with the distribution function given in the
table below, the expected value is: (2)
A. 1.0
B. 2.0
C. 5.0
D. 0.5
E. 0.4
x | 0 1 2 3 4
f(x) | 1 2 4 2 1

5) For a sample of size n = 20, and α = 0.05, tα/2, n-1 can be found from the table to be:
(1)
A. 2.093
B. 2.086
C. 1.729
D. 1.725
E. None of the above
6) A 95% confidence interval for the population mean is calculated to be 75.29 to
81.45. If the confidence level is reduced to 90%, the confidence interval will:
(1)
A. Remain the same
B. Become wider
C. Double in size
D. Become narrower
E. Most likely no longer include the true value of the population mean
7) Given that the variance equals to 4, and zα/2 = 1.96 if the Confidence interval
length should be at most 1.2, what is the required sample size?
(1)
A. 42
B. 43
C. 10
D. 11
E. 7
8) A coin is tossed three times. What is the probability that it lands on head exactly
one time: (2)
A. 0.375
B. 0.125
C. 0.250
D. 0.333
E. 0.500
9) Consider discrete random variable X, with the distribution function given in the
table below, the expected value is: (2)
A. 1.0
B. 2.0
C. 5.0
D. 0.5
E. 0.4
x | 0 1 2 3 4
f(x) | 1 2 4 2 1

Added by Steven C.

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