WGU Intro to Probability and Statistics || 100% Valid Solutions.
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
3. Write all the leaves next to the stem, and rearrange them in increasing order
two Virtues of a stemplot correct answers 1. preserves the data while sorting it
2. when rotated looks like a histogram
Dotplot correct answers a stemplot with dots instead of leaves
Boxplot correct answers Shows the "five number spread": min, Q1, Median, Q2, Max
Y axis is range
Drawn box is interquartile range
Points for outliers, minimum and maximum
Is most useful for showing side by side comparisons
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
3. Write all the leaves next to the stem, and rearrange them in increasing order
two Virtues of a stemplot correct answers 1. preserves the data while sorting it
2. when rotated looks like a histogram
Dotplot correct answers a stemplot with dots instead of leaves
Boxplot correct answers Shows the "five number spread": min, Q1, Median, Q2, Max
Y axis is range
Drawn box is interquartile range
Points for outliers, minimum and maximum
Is most useful for showing side by side comparisons
