Question 26
Which of the following statements about testing a hypothesis using a Z-test is least accurate?
A) A Type I error is rejecting the null hypothesis when it is actually true. B) The calculated Z-statistic determines the appropriate significance level to use. C) If the calculated Z-statistic lies outside the critical Z-statistic range, the null hypothesis can be rejected. D) The confidence interval for a two-tailed test of a population mean at the 5% level of significance is that the sample mean falls between ±1.96 σ/√n of the null hypothesis value. Question 27
The average amount of snow that falls during January in Frostbite
Falls is normally distributed with a mean of 35 inches and a standard deviation of 5 inches. The probability that the snowfall amount in January of next year will be between 40 inches and 26.75 inches is closest to:
A) 68%. B) 79%. C) 95%. D) 87%.
Question 28
Identify the error type associated with the level of significance and the meaning of a 5 percent significance level. Error type α = 0.05 means there is a 5 percent probability of:
A) Type I error rejecting a true null hypothesis
B) Type II error rejecting a true null hypothesis C) Type I error failing to reject a true null hypothesis D) Type II error failing to reject a true null hypothesis Question 29
The possible outcomes for a random variable are described by a continuous uniform distribution with a lower limit of -15 and an upper limit of +25. The probability that the variable has a negative value is closest to:
A) 0.0%. B) 25.5%. C) 37.5%. D) 60.0%. Question 30
The mean return for the population of all stocks on an exchange in the year 20X1 was 5.0%. The mean return from a sample of 20 randomly selected stocks on that exchange in 20X1 was 4.0%. The difference of -1.0% is best defined as the:
A) 1% confidence interval. B) mean sampling difference. C) sampling error. D) standard error of the sample mean.
[此贴子已经被作者于2008-11-8 18:03:13编辑过] | 
发表于 2008-5-26 12:18
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