Reference no: EM13921285

Question 1: Both ordinal and nominal variables are categorical.

• True
• False

Question 2: The time required to drive from Detroit to Lansing is an example of a discrete random variable.

• True
• False

Question 3: Phone numbers, Social Security numbers, and zip codes are examples of numerical variables.

• True
• False

Question 4: If you are in a class where most students do reasonably well on a test but a few pull down the class average, the histogram describing the test scores will indicate a positively-skewed distribution.

• True
• False

Question 5: Some histograms have two or more peaks. This is often an indication that the data come from two or more distinct populations.

• True
• False

Question 6: Statisticians often refer to the pivot tables as contingency tables or crosstabs.

• True
• False

Question 7: The scatterplot is a graphical technique used to describe the relationship between two numerical variables.

• True
• False

Question 8: A variable (or field) is an attribute, or measurement, on members of a population, whereas an observation (or case or record) is a list of all variable values for a single member of a population.

• True
• False

Question 9: A data sample has a mode of 140, a median of 130, and a mean of 120. The distribution of the data is positively skewed.

• True
• False

Question 10: Suppose that a sample of 8 observations has a sample variance of 2.50, then the sum of the squared deviations from the sample mean is 17.50.

• True
• False

Question 11: If two data sets have the same range, the smallest and largest observations in both sets should be the same

• True
• False

Question 12: The standard deviation is measured in original units, such as dollars and pounds.

• True
• False

Question 13: The median is one of the most frequently used measures of variability.

• True
• False

Question 14: It is possible that the data points are close to a curve and have a correlation close to 0, because correlation is relevant only for measuring linear relationships.

• True
• False

Question 15: Numerical variables can be subdivided into which two types?

• Diverse and categorical
• Discrete and continuous
• Nominal and progressive
• Cross-sectional and discrete

Question 16: A sample of a population taken at one particular point in time is categorized as:

• categorical
• discrete
• cross-sectional
• time-series

Question 17: A scatterplot allows one to see:

• whether there is any relationship between two variables
• what type of relationship there is between two variables
• Both (a) and (b) are correct
• Neither (a) nor (b) is correct

Question 18: A bimodal histogram is often an indication that the:

• data are incorrect
• data are inconclusive
• sample is not representative of the population
• data come from two or more distinct populations

Question 19: A population includes:

• only people
• only households
• all objects of interest in a particular study
• only machines

Question 20: Which of the following statements are false?

• A categorical variable is nominal if there is natural ordering of its possible values.
• A variable is numerical if meaningful arithmetic can be performed on it.
• Zip codes are usually treated as categorical variables, although they appear to be numerical.
• All of the above

Question 21: Which of the following are true statements of pivot tables?

• They allow us to "slice and dice" data in a variety of ways.
• Statisticians often refer to them as contingency tables or crosstabs.
• Pivot tables can list counts, averages, sums, and other summary measures, whereas contingency tables list only counts.
• All of the options.

Question 22: Which of the following are considered measures of association?

• Mean and variance
• Variance and correlation
• Correlation and covariance
• Covariance and variance

Question 23: The mode is best described as the

• middle observation
• same as the average
• 50th percentile
• most frequently occurring value

Question 24: Which of the following statistics is not a measure of central location?

• Mean
• Median
• Mode
• Interquartile range

Question 25: The correlation coefficient is always a value between

• - 1 and 0
• 0 and +1
• 0.0 and 100
• -1 and +1
• -1 and 100

Question 26: For a boxplot, the vertical line inside the box indicates the location of the

• mean
• median
• mode
• minimum value
• maximum value

Question 27: For a boxplot, the box itself represents what percent of the observations?

• lower 25%
• middle 50%
• upper 75%
• upper 90%

Question 28: Which of the following statements is true?

• The sum of the deviations from the mean is always zero
• The sum of the squared deviations from the mean is always zero
• The range is always smaller than the variance
• The standard deviation is always smaller than the variance

Question 29: A sample of 20 observations has a standard deviation of 4. The sum of the squared deviations from the sample mean is:

• 400
• 320
• 304
• 288

Question 30: A data set from a sample of 399 Michigan families was collected. The characteristics of the data include family size (large or small), number of cars owned by family (1, 2, 3, or 4), and whether family owns a foreign car. Excel produced the pivot table shown below.

Use this pivot table to determine how family size and number of cars owned influence the likelihood that a family owns a foreign car.

Question 31: A real estate agent has gathered information on 40 houses that were recently sold in a local community. The data she collected represent the following variables: the selling price of each house (in thousands of dollars), the appraised value of each house (in thousands of dollars), the size of the house (in hundreds of square feet), and the number of bedrooms.

Indicate whether each of the four variables is continuous or discrete.

Question 32: A recent survey data collected from 1000 randomly selected Internet users. The characteristics of the users include their gender, age, education, marital status and annual income. Using Excel, the following pivot tables were produced.

Approximate the percentage of these Internet users who are married with formal education beyond high school.

Question 33: A recent survey data collected from 1000 randomly selected Internet users. The characteristics of the users include their gender, age, education, marital status and annual income. Using Excel, the following pivot tables were produced.

Approximate the percentage of these Internet users who are in the 58-71 age group.

Question 34: The histogram below represents scores achieved by 250 job applicants on a personality profile.

Sixty percent of the job applicants scored below what value?

Question 35: The histogram below represents scores achieved by 250 job applicants on a personality profile.

How many job applicants scored between 10 and 30?

Question 36: A manager for Marko Manufacturing, Inc. has recently been hearing some complaints that women are being paid less than men for the same type of work in one of their manufacturing plants. The boxplots shown below represent the annual salaries for all salaried workers in that facility (40 men and 34 women).

Would you conclude that there is a difference between the salaries of women and men in this plant? Justify your answer.

Question 37: A statistics professor has just given a final examination in his statistical inference course. He is particularly interested in learning how his class of 40 students performed on this exam. The scores are shown below.

77 81 74 77 79 73 80 85 86 73
83 84 81 73 75 91 76 77 95 76
90 85 92 84 81 64 75 90 78 78
82 78 86 86 82 70 76 78 72 93

What are the mean and median scores on this exam? Explain why the mean and median are different.

Question 38: An economic development researcher wants to understand the relationship between the average monthly expenditure on utilities for households in a particular middle-class neighborhood and each of the following household variables: family size, approximate location of the household within the neighborhood, and indication of whether those surveyed owned or rented their home, gross annual income of the first household wage earner, gross annual income of the second household wage earner (if applicable), size of the monthly home mortgage or rent payment, and the total indebtedness (excluding the value of a home mortgage) of the household.

The correlation for each pairing of variables is shown in the table below:

Which of the variables appears to have the weakest linear relationship with the household's average monthly expenditure on utilities?

Question 39: The following data represent the number of children in a sample of 10 families from Chicago: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2.

• Compute the mean number of children.
• Compute the median number of children.
• Is the distribution of the number of children symmetrical or skewed? Why?