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STT 215 Exam 1 Study Guide 100%
Verified.
What is statistics? - Answer✔Collection or gathering of data
Displaying, analyzing, and summarizing data
Inferring information from data
Cases - Answer✔The objects described by a set of data. May be customers, companies, subjects
in a study, or other subjects (observations/individuals).
Label - Answer✔A special variable used in some data sets to distinguish different cases.
Example: Patient A, Patient B, Patient C, etc.
Variable - Answer✔A characteristic that varies among individuals in a population or in a sample
(a subset of a population).
Example: age, height, blood pressure, ethnicity, leaf length, first language
Distribution - Answer✔Tells us what values the variable takes and how often it takes these
values.
Categorical variable - Answer✔Something that falls into one of several categories. What can be
counted is the count or proportion of individuals in each category.
Example: blood type (A, B, AB, O), hair color, ethnicity
1
, ©JASONMcCONNELL 2025 ALL RIGHTS RESERVED
Quantitative (numerical) variable - Answer✔Something that can be counted or measured for
each individual and then added, subtracted, averaged, etc. across individuals in the population.
Example: height, age, blood cholesterol level
Quantitative data: discrete versus continous - Answer✔Discrete if the possible values are
isolated points on the number line.
Continuous if the set of possible values forms an entire interval on the number line.
Ways to represent categorical data - Answer✔Frequency / Relative Frequency distribution
Bar graph
Pie chart
Ways to represent numerical data - Answer✔Frequency distribution
Stemplot (stem-and-leaf plot)
Histogram
Ways to represent bivariate numerical data - Answer✔Scatter plot
Bar graph - Answer✔Each category is represented by a bar. The bar's height shows the count
(or sometimes the percentage) for that particular category.
Pie chart - Answer✔Peculiarity: the slices mist represent the parts of one whole (1 or 100%).
The size of a slice depends on what percent of the whole this category represents.
Relative frequency - Answer✔(frequency) / (number of observations in the data set)
Stemplot - Answer✔(Also called a stem-and-leaf plot) Each observation is represented by a
stem, consisting of all digits except the final one, which is the leaf.
2
STT 215 Exam 1 Study Guide 100%
Verified.
What is statistics? - Answer✔Collection or gathering of data
Displaying, analyzing, and summarizing data
Inferring information from data
Cases - Answer✔The objects described by a set of data. May be customers, companies, subjects
in a study, or other subjects (observations/individuals).
Label - Answer✔A special variable used in some data sets to distinguish different cases.
Example: Patient A, Patient B, Patient C, etc.
Variable - Answer✔A characteristic that varies among individuals in a population or in a sample
(a subset of a population).
Example: age, height, blood pressure, ethnicity, leaf length, first language
Distribution - Answer✔Tells us what values the variable takes and how often it takes these
values.
Categorical variable - Answer✔Something that falls into one of several categories. What can be
counted is the count or proportion of individuals in each category.
Example: blood type (A, B, AB, O), hair color, ethnicity
1
, ©JASONMcCONNELL 2025 ALL RIGHTS RESERVED
Quantitative (numerical) variable - Answer✔Something that can be counted or measured for
each individual and then added, subtracted, averaged, etc. across individuals in the population.
Example: height, age, blood cholesterol level
Quantitative data: discrete versus continous - Answer✔Discrete if the possible values are
isolated points on the number line.
Continuous if the set of possible values forms an entire interval on the number line.
Ways to represent categorical data - Answer✔Frequency / Relative Frequency distribution
Bar graph
Pie chart
Ways to represent numerical data - Answer✔Frequency distribution
Stemplot (stem-and-leaf plot)
Histogram
Ways to represent bivariate numerical data - Answer✔Scatter plot
Bar graph - Answer✔Each category is represented by a bar. The bar's height shows the count
(or sometimes the percentage) for that particular category.
Pie chart - Answer✔Peculiarity: the slices mist represent the parts of one whole (1 or 100%).
The size of a slice depends on what percent of the whole this category represents.
Relative frequency - Answer✔(frequency) / (number of observations in the data set)
Stemplot - Answer✔(Also called a stem-and-leaf plot) Each observation is represented by a
stem, consisting of all digits except the final one, which is the leaf.
2
