stats half

QUESTION 1

1. Data that are categorical but can be rank-ordered in a meaningful way are called:

		Nominal
		Interval
		Ordinal
		Ratio

3.5 points   

QUESTION 2

1. The “standard normal distribution” table (i.e., the z-table) shows the relationship between two variables:  the z-score and a probability (i.e., an area under the normal distribution).

 True

 False

3.5 points   

QUESTION 3

1. Given a normally distributed variable (x), the formula:  z  =  (x - µ) ÷ σ  can be used to determine the value of x at a specific point on the x-axis, if you know the z-score.

 True

 False

3.5 points   

QUESTION 4

1. A probability distribution is a theoretical but a frequency distribution is based on actual results/data.

 True

 False

3.5 points   

QUESTION 5

1. Which of the following symbols represents the variance of the population?

		σ2
		σ
		μ
		s2

3.5 points   

QUESTION 6

1. When calculating a binomial probability, the answer must be in the range of 0.00 to 1.00.

 True

 False

3.5 points   

QUESTION 7

1. Which of the following is NOT an assumption for (property of) the binomial distribution?

		The trials are independent
		Two outcomes are possible on each trial in the experiment
		The experiment consists of n identical trials
		The probabilities of success and failure at each trial must be equal

3.5 points   

QUESTION 8

1. A negative value of Z indicates:

		The number of standard deviations a measurement is to the right of the mean
		The number of standard deviations a measurement is to the left of the mean
		That a mistake has been made in computations, since Z cannot be negative
		The area corresponding to the z-score is negative

3.5 points   

QUESTION 9

1. A variable with equal distances between points on a scale, which also has a true meaningful zero is:

		Ordinal
		Cardinal
		Ratio
		Nominal

3.5 points   

QUESTION 10

1. A probability distribution showing the probability of x successes in n trials, where the probability of success does not change from trial to trial, is termed a:

		uniform probability distribution
		binomial probability distribution
		t distribution
		normal probability distribution

3.5 points   

QUESTION 11

1. For which level(s) of measurement are arithmetic operations inappropriate?

		The ratio scale
		The interval scale
		Both the ratio and interval scales
		The nominal scale

3.5 points   

QUESTION 12

1. In a binomial experiment:

		The probability does not change from trial to trial
		The probability does change from trial to trial
		The probability could change from trial to trial, depending on the situation under consideration
		None of the above

3.5 points   

QUESTION 13

1. In constructing a frequency distribution, as the number of classes are decreased, the class width:

		Decreases
		Remains unchanged
		Increases
		Can increase or decrease depending on the data values

3.5 points   

QUESTION 14

1. The measure of central tendency that is the point at which half the scores fall above and half the scores fall below is the:

		Mode
		Range
		Median
		Mean

3.5 points   

QUESTION 15

1. In a sample of 800 students in a university, 240, or 30%, are Business majors. The 30% is an example of:

		A sample
		A population
		Statistical inference
		Descriptive statistics

3.5 points   

QUESTION 16

1. Given a normally distributed variable (x), if you know that for a value of x = -27 the z-score = 0.67, what is the probability of any x value being below -27?

		0.9965
		0.7486
		-0.2514
		0.2514

3.5 points   

QUESTION 17

1. Data which uses numerical values, has an equal distance between points on the scale, and does not have an absolute zero is:

		Nominal
		Ordinal
		Normal
		Interval

3.5 points   

QUESTION 18

1. The primary method for controlling/minimizing sampling error is to:

		Increase sampling bias
		Take multiple samples
		Select samples from a heterogeneous population
		Increase sample size

3.5 points   

QUESTION 19

1. A numerical value used as a summary measure for a sample, such as sample mean, is known as a:

		Population parameter
		Sample parameter
		Sample statistic
		Population mean

3.5 points   

QUESTION 20

1. The summaries of data, which may be tabular, graphical, or numerical, are referred to as:

		Inferential statistics
		Descriptive statistics
		Statistical inference
		Report generation

3.5 points   

QUESTION 21

1. The Quickie Sales Corporation has just been given a sales estimate for the upcoming quarter.  The estimate indicates that sales (in millions of dollars) will be normally distributed with µ = 325 and σ = 60.  Assuming this estimate is accurate, what is the probability that Quickie will have quarterly sales in excess of $350 million?

QUESTION 22

The U.S. Postal Service handles seven basic types of letters and cards:  third class, second class, first class, air mail, special delivery, registered and certified.  The mail volume during 1977 is given in the table below.  What was the average revenue per ounce for these services during the year?

Type of Mailing	Ounces Delivered (in millions)	Price per Ounce
Third class	16,400	$0.05
Second class	24,100	0.08
First class	77,600	0.13
Air Mail	1,900	0.17
Special delivery	1,300	0.35
Registered	750	0.40
Certified	800	0.45

QUESTION 23

1. Here are the ages of 30 people who bought CD players at Symphony Music Shop last week:  26, 37, 40, 18, 15, 45, 32, 68, 31, 37, 20, 32, 15, 27, 46, 44, 62, 58, 30, 42, 22, 26, 44, 41, 34, 55, 50, 63, 29, 22.  Construct a frequency distribution (table) with 6 classes to summarize these data.