A standard normal distribution is a normal distribution with:
a. a mean of zero and a standard deviation of one
b. a mean of one and a standard deviation of zero
c. a mean zero and a standard deviation of zero
d. a mean of one and a standard deviation of one
e. none of these
Q. 2The z-test can be used to determine whether two population means are equal.
Indicate whether the statement is true or false
Q. 3Briefly discuss the assumptions for Inferences about Rank Correlation.
Q. 4The z-score representing the third quartile of the standard normal distribution is:
a. 0.67
b. 0.67
c. 1.28
d. 1.28
e. 0.33
Q. 5If the probability of committing a Type I error for a given test is to be decreased, then for a fixed sample size n, which of the following statements is true?
a. The power of the test will increase.
b. The probability of committing a Type II error will increase.
c. The probability of committing a Type II error will decrease.
d. A two-tailed test must be used.
e. The probability of committing a Type II error will decrease and a two-tailed test must be used.
Q. 6Which of the following statements is false?
a. The Spearman rank correlation test of significance will result in a failure to reject the null hypothesis when r, is close to zero.
b. The Spearman rank correlation test of significance will result in a rejection of the null hypothesis when r, is found to be close to + 1 or -1 .
c. One of the assumptions for inferences about rank correlation is that the variables are nominal.
d. None of the above.
Q. 7Let z1 be a z score that is unknown but identifiable by position and area. If the symmetrical area between a negative z1 and a positive z1 is 0.8132, then the value of z1 is:
a. z = 1.32
b. z = 0.89
c. z = 2.64
d. z = 1.78
e. z = 8.13
Q. 8In formulating the null and alternative hypothesis, which of the following would be an acceptable null hypothesis?
a. The population mean is greater than 20.
b. The population mean is smaller than 20.
c. The population mean is equal to 20.
d. The population mean is not equal to 20.
e. None of these.
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