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