STAT 3321 – Final, Spring, 2007 – Green Exam - Printed Name_______________________
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4 Which of the following is true about the sampling distribution of the sample mean?
a. The shape of the sampling distribution is always normal even for small sample sizes.
b. The standard deviation of the sampling distribution is always equal to the population standard deviation.
c. The sampling distribution is a list of all possible sample sizes.
d. All of these are true.
e. The mean of the sampling distribution is always equal to the population mean .
5 When trying to estimate the population mean, the typical error in the sample mean is also called the:
a. standard error of the mean.
b. finite population correction factor.
c. central limit theorem.
d. population standard deviation.
e. margin of error
6 Which of the following would be an appropriate alternative hypothesis?
a. The mean of a population is equal to 70.
b. The mean of a sample is greater than 55
c. The mean of a sample is equal to 55.
d. The mean of a population is greater than 70..
e. the sample standard deviation is > 3
7 The expected number of heads in 100 tosses of an unbiased coin is:
8 A 98% confidence interval estimate for a population mean is determined to be 75.38 to 86.52. If the confidence level is reduced to 90%, the confidence interval:
a. becomes narrower.
b. increases its confidence
c. remains the same.
d. becomes wider.
e. None of these choices.
9 Which of the following measures can be used with both numerical and categorical variables?
a. the mode
b. the median
c. the arithmetic mean
d. the standard deviation
e. the scatter plot
10 Researchers determine that 60 Kleenex tissues is the average number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: (x= 52 and s = 22. Using the sample information provided, what is the value of the test statistic?:
a. t = (52 - 60)/(22/100)
b. t = (52 - 60)/(22/10)
c. t = (52 - 60)/22
d. t = (52 - 60)/(22/1002 )
e. none of the above
11 A normally distributed population has a mean of 60 and a standard deviation of 10. You obtain a random sample of size 25.The probability that the sample mean will be smaller than 56 is:
e. none of the above
12 In performing a regression analysis involving two numerical variables, we are assuming:
a. All of these choices are correct.
b. the variances of x and y are equal.
c. y has the same variation for each x value..
d. that x and y are independent.
e. the distribution of x is normal.
13 The classification of student major (accounting, economics, management, marketing, other) is an example of:
a. a categorical or qualitative random variable.
b. a discrete random variable.
c. a continuous random variable.
d. a parameter.
e. a scatter plot
14 In the simple linear regression model, the slope represents the:
a. average change in x per unit change in y