WGU Intro to Probability and Statistics
Exam With 100% Correct Answers
Population - correct answers ✔✔The entire group that is the target of interest, not just people.
Eg, "the population of 1 bedroom apartments"
Sample - correct answers ✔✔A subgroup of the population. Eg, "the 1 bedroom apartments
with dishwashers."
Steps in the statistics process - correct answers ✔✔1. PRODUCE DATA (by studying a sample of
the population)
2. EXPLORATORY DATA ANALYSIS (Summarize data.)
3. PROBABILITY ANALYSIS (Determine how the sample may differ from the population.)
4. INFERENCE (draw conclusions)
Data - correct answers ✔✔pieces of info about individuals organized into variables
Individual - correct answers ✔✔a particular person or object
Variable - correct answers ✔✔a particular characteristic of the individual
Dataset - correct answers ✔✔a set of data identified with particular circumstances. Typically
displayed in tables with rows as the individuals and columns as the variables
Quantitative vs Categorical/Qualitative variables - correct answers ✔✔Quantitaive: Numerical
values. Represent a measurement.
,Categorical: category or label values into which individuals are grouped.
Three steps in Exploratory Data Analysis - correct answers ✔✔1. Organize and SUMMARIZE raw
data
2. DISCOVER important features and patterns and striking deviations.
3. INTERPRET findings in the context of the problem
Examining Distributions - correct answers ✔✔exploring data obtained from one variable at a
time
Examining Relationships - correct answers ✔✔exploring data obtained from two variables at a
time
Distribution - correct answers ✔✔what values the variable takes, how often
Three types of graphical displays of categorical distributions - correct answers ✔✔1. Pie Charts
2. Bar Charts
3. Pictogram
Bins - correct answers ✔✔ranges of data to make charting easier, like a bar chart where each
bar shows a range like 70-80%
Numerical Summaries - correct answers ✔✔category counts and percentages
Four types of Graphical displays of Quantitative Variables - correct answers ✔✔1. Histogram
2. Stemplot
3. Dotplot
, 4. Boxplot
Histogram - correct answers ✔✔like a bar chart but the x axis is numerical, in order. Eg: x axis is
years, y axis is Men's income and Women's income. Or, the x axis is number of hours studied,
and y axis is number of students falling into each number of hours studied category.
4 ways to interpret a histogram - correct answers ✔✔1. Shape - Symmetry/Skewness, Peakness
(Modality)
2. Center - midpoint
3. Spread - approx range covered by all the data
4. Outliers - observations that fall outside overall pattern
Symmetric distributions (on a histogram) - correct answers ✔✔look symmetric. can be multi-
peaked, but symmetrical
Skewness (on a histogram) - correct answers ✔✔data is skewed to the right or left because
outliers. (Careful because the histogram looks heavy to the opposite side than to that which it is
skewed. Think of the outliers as pulling a long tail out from the main data, making it not
symmetrical.)
Peakedness (on a histogram) (three types) - correct answers ✔✔1. Unimodal (single peaked)
distribution
2. Bimodal (double peaked) distribution
3. Uniform distribution (Many peaks, all the same)
Stemplot (or stem and leaf plot) - correct answers ✔✔1. Write all the "stems" down in a list, in
ascending numerical order. (The stems are all the numbers but the right most number. Eg:
dataset 34 35 36 347 367 the stems are 3, 3, 3, 34, 36, but you only use each identical stem
once, so it would be 3, 34, 36)
2. Draw a line to the right of the list
Exam With 100% Correct Answers
Population - correct answers ✔✔The entire group that is the target of interest, not just people.
Eg, "the population of 1 bedroom apartments"
Sample - correct answers ✔✔A subgroup of the population. Eg, "the 1 bedroom apartments
with dishwashers."
Steps in the statistics process - correct answers ✔✔1. PRODUCE DATA (by studying a sample of
the population)
2. EXPLORATORY DATA ANALYSIS (Summarize data.)
3. PROBABILITY ANALYSIS (Determine how the sample may differ from the population.)
4. INFERENCE (draw conclusions)
Data - correct answers ✔✔pieces of info about individuals organized into variables
Individual - correct answers ✔✔a particular person or object
Variable - correct answers ✔✔a particular characteristic of the individual
Dataset - correct answers ✔✔a set of data identified with particular circumstances. Typically
displayed in tables with rows as the individuals and columns as the variables
Quantitative vs Categorical/Qualitative variables - correct answers ✔✔Quantitaive: Numerical
values. Represent a measurement.
,Categorical: category or label values into which individuals are grouped.
Three steps in Exploratory Data Analysis - correct answers ✔✔1. Organize and SUMMARIZE raw
data
2. DISCOVER important features and patterns and striking deviations.
3. INTERPRET findings in the context of the problem
Examining Distributions - correct answers ✔✔exploring data obtained from one variable at a
time
Examining Relationships - correct answers ✔✔exploring data obtained from two variables at a
time
Distribution - correct answers ✔✔what values the variable takes, how often
Three types of graphical displays of categorical distributions - correct answers ✔✔1. Pie Charts
2. Bar Charts
3. Pictogram
Bins - correct answers ✔✔ranges of data to make charting easier, like a bar chart where each
bar shows a range like 70-80%
Numerical Summaries - correct answers ✔✔category counts and percentages
Four types of Graphical displays of Quantitative Variables - correct answers ✔✔1. Histogram
2. Stemplot
3. Dotplot
, 4. Boxplot
Histogram - correct answers ✔✔like a bar chart but the x axis is numerical, in order. Eg: x axis is
years, y axis is Men's income and Women's income. Or, the x axis is number of hours studied,
and y axis is number of students falling into each number of hours studied category.
4 ways to interpret a histogram - correct answers ✔✔1. Shape - Symmetry/Skewness, Peakness
(Modality)
2. Center - midpoint
3. Spread - approx range covered by all the data
4. Outliers - observations that fall outside overall pattern
Symmetric distributions (on a histogram) - correct answers ✔✔look symmetric. can be multi-
peaked, but symmetrical
Skewness (on a histogram) - correct answers ✔✔data is skewed to the right or left because
outliers. (Careful because the histogram looks heavy to the opposite side than to that which it is
skewed. Think of the outliers as pulling a long tail out from the main data, making it not
symmetrical.)
Peakedness (on a histogram) (three types) - correct answers ✔✔1. Unimodal (single peaked)
distribution
2. Bimodal (double peaked) distribution
3. Uniform distribution (Many peaks, all the same)
Stemplot (or stem and leaf plot) - correct answers ✔✔1. Write all the "stems" down in a list, in
ascending numerical order. (The stems are all the numbers but the right most number. Eg:
dataset 34 35 36 347 367 the stems are 3, 3, 3, 34, 36, but you only use each identical stem
once, so it would be 3, 34, 36)
2. Draw a line to the right of the list
