MKTG 343 Exam 1

IQR =

3rd quartile - 1st quartile

Categorical data is ordinal when there is______

a natural order to its values

Scatterplot is

a scatter of point where each point denotes the values of an observation for two selected variables

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

a side-by-side plot or side-by-side pivot table

Correlation

a unit-less quantity that is unaffected by the measurement scale, single number summary of a scatter plot

Gender and states are examples of ______ data

categorical

Business Analytics

combination of skills, technologies, applications etc to gain insight into their business based on data to drive business planning

Displaying all correlations between 0.6 and 0.999 on a scatterplot as green and all correlations between -1.0 and -0.6 as red is known as:

conditional formatting

The most useful numerical summary measure is

correlation

We study relationships among numerical variables using:

covariance, scatterplot charts, correlation

The decision making process includes

decision analysis for problems with uncertainty, sensitivity analysis, optimization techniques for problems with no uncertainty

Covariance

essentially an average of products of deviations from means

Both ordinal and nominal variables are categorical (t/f)

false

Correlation can be affected by the measurement scales applied to X and Y variables (t/f)

false

Supposed that a sample of 10 observations has a standard deviation of 3. Then the sum of the squared deviations from the sample mean is 30 (t/f)

false

The cutoff for defining a large correlation is 0.5 (t/f)

false

We cannot attempt to interpret correlations numerically, with the one possible exception of indicating whether they are positive or negative. (t/f)

false

Box-Whisker Plots

helps us better understand skewness

prescriptive

how can we make it happen

The difference between the first and the third quartile is called the

interquartile range

What are the 3 most common measures of central tendency?

mean, median, mode

Results =

models + findings

If the line falls from left to right the relationship is

negative

Left skewness means its

negatively skewed

Comparison Problem

occurs whenever you want to compare a numerical measure across two or more subpopulations

Right skewness means its

positively skewed

If the straight line rises from left to right the relationship is

positivve

The primary interest in data analysis is usually in ____________ between variables

relationships

Researchers may try to gain insight into the characteristics of a population by examining a(n)__________ of the population

sample

The most useful graph is a

scatterplot

value > .5

strong correlation

Kurtosis has to do with

the "fatness" of the tails of the distribution relative to the tails of a normal distribution

How is the median defined if the number of observations is even?

the average of the two middle obervations

A histogram is

the most common type of chart for showing the distribution of a numerical variable

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

the points on a scatterplot cluster tightly around a downward/upward sloping straight line

Data analysis includes:

the search for relationships in data, data inference and data description

Skewness occurs when

there is a lack of symmetry

A frequency table indicates how many observations fall within a category, and a histogram is its graphical analog (t/f)

true

Age, height, and weight are examples of numerical data (t/f)

true

An example of a joint category of two variables is the count of all non-smokers who are also non-drinkers (t/f)

true

As a graphical tool, the histogram is ideal for showing whether the distribution of a numerical variable is symmetric or skewed (t/f)

true

If the coefficient of correlation r = 0 .80, the standard deviations of X and Y are 20 and 25, respectively, then Cov(X, Y) must be 400. (t/f)

true

In the term "frequency table", frequency refers to the counts of observations in specified categories (t/f)

true

Strongly related variables may have a correlation close to zero if the relationship is nonlinear (t/f)

true

The advantage that correlation has over covariance is that the former has a set lower and upper limit (t/f)

true

The authors of the Business Analytics: Data Analysis & Decision Making text describe three types of models: graphical models, algebraic models, and spreadsheet models. (t/f)

true

To form a scatterplot of X versus Y, X and Y must be paired variables (t/f)

true

We must deal with uncertainty when we make inferences from data and search for relationships in data, or when we use decision trees to help make decisions. (t/f)

true

Stacked Chart

two "long" variables

value < .5

weak correlation

descriptive

what happened

predictive

what will happen

diagnostic

why did it happen