Managerial Decision Making Test 1

Which of the following indicates how many observations fall into various categories?

The frequency table

Which of the following statements are false??

The modeling process discussed in Data Analysis & Decision Making book is five- step process

Correlation and covariance measure

The strength and direction of a linear relationship between two numerical variables

Which of the following are the two most commonly used measures of variability?

Variance and standard deviation

Generally speaking, if two variables are unrelated (as one increases, the other shows no pattern), the covariance will be

a positive or negative number close to zero

We are usually on the lookout for large correlations near

a. +1 c. Either of these options b. -1 (c is correct)

Which of the following statements are false?

a. Contingency tables are traditional statistical terms for pivot tables that list counts. b. Time series plot is a chart showing behavior over time of a time series variable. c. Pivot table is a table in Excel that summarizes data broken down by one or more numerical variables. d. None of these options

We study relationships among numerical variables using

a. Correlation b. Covariance c. Scatterplots d. All of these options

Tables used to display counts of a categorical variable are called

a. Crosstabs c. Both of these options b. Contingency tables (c is correct)

Which of the following are possible categorizations of data type?

a. Numerical versus categorical (with subcategories nominal, ordinal) b. Discrete versus continuous c. Cross-sectional versus time series d. All of these options (d is correct)

Example of comparison problems include

a. Salary broken down by male and female subpopulations b. Cost of living broken down by region of a country c. Recovery rate for a disease broken down by patients who have taken a drug and patients who have taken a placebo d. Starting salary of recent graduates broken down by academic major e. All of these options (e is correct)

A useful way of comparing the distribution of a numerical variable across categories of some categorical variable is

a. Side-by-side boxplots c. Both of these options b. Side-by-side histograms (c is correct)

We can infer that there is a strong relationship between two numerical variables when

a. The points on a scatterplot cluster tightly around an upward sloping straight line b. The points on a scatterplot cluster tightly around a downward sloping straight line c. Either of these options

Which of the following are true statements of pivot tables?Which of the following are true statements of pivot tables?

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

Data analysis includes

a. data description c. the search for relationships in data b. data inference d. All of these options(d is correct)

The decision making process includes

a. optimization techniques for problems with no uncertainty b. decision analysis for problems with uncertainty c. sensitivity analysis d. All of the above (d is correct)

The median can also be described as:The median can also be described as:

a. the middle observation when the data values are arranged in ascending order b. the second quartile c. the 50th percentile d. All of these options

A histogram that has exactly two peaks is called a

bimodal distribution

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

cross-sectional

Data that arise from counts are called:Data that arise from counts are called:

discrete data

In a histogram, the percentage of the total area which must be to the left of the median is:

exactly 50%

The difference between the first and third quartile is called the

interquartile range

The length of the box in the boxplot portrays the

interquartile range

For a boxplot, the point inside the box indicates the location of the

mean

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

median

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

middle 50%

The mode is best described as the

most frequently occurring value

The tool that provides useful information about a data set by breaking it down into subpopulations is the:

pivot table

In order for the characteristics of a sample to be generalized to the entire population, it should be:

representative of the population

Researchers may gain insight into the characteristics of a population by examining a

sample of the population

The modeling process discussed in Data Analysis & Decision Making book is a

seven-step process

A histogram that has a single peak and looks approximately the same to the left and right of the peak is called

symmetric

A variable is classified as ordinal if

there is a natural ordering of categories

When we look at a time series plot, we usually look for which two things?

"Is there an observable trend?" and "Is there a seasonal pattern?"

If Cov(X,Y) = - 16.0, variance of X = 25, variance of Y = 16 then the sample coefficient of correlation r is

- 0.80

A perfect straight line sloping downward would produce a correlation coefficient equal to

-1

Expressed in percentiles, the interquartile range is the difference between the

25th and 75th percentiles

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

304

The average score for a class of 30 students was 75. The 20 male students in the class averaged 70. The 10 female students in the class averaged

85

Suppose that a histogram of a data set is approximately symmetric and "bell shaped". Approximately what percent of the observations are within two standard deviations of the mean?

95%

If a value represents the 95th percentile, this means that

95% of all values are below this value

If the correlation is close to 0, then we expect to see

A cluster of points with no apparent relationship

The correlation is best interpreted

Along with the corresponding scatterplot

Which of the following are considered measures of association?

Correlation and covariance

To examine relationships between two categorical variables, we can use

Counts and corresponding charts of the counts

Numerical variables can be subdivided into which two types?

Discrete and continuous

If data is stored in a database package, which of the following terms are typically used?

Fields and records

The limitation of covariance as a descriptive measure of association is that it

Is very sensitive to the units of the variables

Which of the following are the three most common measures of central location?

Mean, median, and mode

Which of the following is not one of the steps in the modeling process?

Select scale for model