PBSI 245 EXAM 2 QUESTIONS WITH VERIFIED
ACCURATE ANSWERS
What is a categorical variable? - Answers -A characteristic of an individual that takes
on values that are names or labels.
What is a quantitative variable? - Answers -Quantitative variables are numeric like:
Height, age, number of cars sold, SAT score
What is a rate ? - Answers -the ratio of two measurements with different units. Very
important parameter that's used with confidence.
What are counts? - Answers -number of cases, think of tally marks. not as reliable as
rates.
What are traits that make a clear table? - Answers -* Clear tables
-titles on both axes (y and x)
- no roundoff errors (entries don't add to the total)
*Distribution
- displays what values a variable takes
Characteristics of a pie chart - Answers --display how a whole is divided into parts
-parts make a whole
-only useful if you have all the categories
Characteristics of bar graphs - Answers --display a single number representing each
category (height of each bar)
-ideal for making comparisons of the sizes of categories
-useful to display an entire distribution and/or few categories
Characteristics of a violin plot - Answers --better reflects the distribution of data
-compares distributions of groups
- does NOT reflect sample size
Characteristics of a pictogram - Answers --DO NOT USE
-bar graph with pictures instead of bars
Characteristics of a line graph - Answers --used to display how a quantitative variable
changes over time
-time is usually plotted on the x-axis (horizontal axis)
-the y-axis changes depending on what you are measuring
what is the trend line of a graph? - Answers -long-term upwards/downwards movement
over time
, What is the "overall pattern" of a graph? - Answers -Overall assessment of the trends
and shapes of a distribution
What are striking deviations? - Answers -Striking differences from the overall pattern.
What is seasonal variation? - Answers -Pattern that repeats itself at known intervals of
time
Characteristics of a histogram - Answers --Most common graph to show a data
distribution
-used to plot counts or frequency of data values
-does NOT display change over a period of time
What are the "measures of statistical dispersion"? - Answers -Variance, Standard
deviation, and interquartile range
What are important things in any graph of data? - Answers --Overall pattern and
striking deviations from that pattern. The overall pattern describes the center and
variability. Describes the shape of the histogram.
Characteristics of a stem plot? - Answers --Used for small data sets
- Presents more detailed information
When a histogram has symmetrical distribution it has...? - Answers -Mean = Median
When a histogram is positively skewed... - Answers -Mean > median
When a histogram is negatively skewed... - Answers -Mean < Median
What are the measures of central tendency? - Answers -Mean, median, and mode
What are the five number categories? - Answers -Median, mean, mode, minimum,
maximum
What are the measures of variability? - Answers -1st and 3rd quartiles
How do you find quartile 1? - Answers -Quartile 1
-median of the observations whose positions are ordered list are to the left of the overall
median
How do you find quartile 3? - Answers -Median of the observations whose positions in
the ordered list are to the right of overall median
What percentage of observations lie below the 3rd quartile? - Answers -75%
ACCURATE ANSWERS
What is a categorical variable? - Answers -A characteristic of an individual that takes
on values that are names or labels.
What is a quantitative variable? - Answers -Quantitative variables are numeric like:
Height, age, number of cars sold, SAT score
What is a rate ? - Answers -the ratio of two measurements with different units. Very
important parameter that's used with confidence.
What are counts? - Answers -number of cases, think of tally marks. not as reliable as
rates.
What are traits that make a clear table? - Answers -* Clear tables
-titles on both axes (y and x)
- no roundoff errors (entries don't add to the total)
*Distribution
- displays what values a variable takes
Characteristics of a pie chart - Answers --display how a whole is divided into parts
-parts make a whole
-only useful if you have all the categories
Characteristics of bar graphs - Answers --display a single number representing each
category (height of each bar)
-ideal for making comparisons of the sizes of categories
-useful to display an entire distribution and/or few categories
Characteristics of a violin plot - Answers --better reflects the distribution of data
-compares distributions of groups
- does NOT reflect sample size
Characteristics of a pictogram - Answers --DO NOT USE
-bar graph with pictures instead of bars
Characteristics of a line graph - Answers --used to display how a quantitative variable
changes over time
-time is usually plotted on the x-axis (horizontal axis)
-the y-axis changes depending on what you are measuring
what is the trend line of a graph? - Answers -long-term upwards/downwards movement
over time
, What is the "overall pattern" of a graph? - Answers -Overall assessment of the trends
and shapes of a distribution
What are striking deviations? - Answers -Striking differences from the overall pattern.
What is seasonal variation? - Answers -Pattern that repeats itself at known intervals of
time
Characteristics of a histogram - Answers --Most common graph to show a data
distribution
-used to plot counts or frequency of data values
-does NOT display change over a period of time
What are the "measures of statistical dispersion"? - Answers -Variance, Standard
deviation, and interquartile range
What are important things in any graph of data? - Answers --Overall pattern and
striking deviations from that pattern. The overall pattern describes the center and
variability. Describes the shape of the histogram.
Characteristics of a stem plot? - Answers --Used for small data sets
- Presents more detailed information
When a histogram has symmetrical distribution it has...? - Answers -Mean = Median
When a histogram is positively skewed... - Answers -Mean > median
When a histogram is negatively skewed... - Answers -Mean < Median
What are the measures of central tendency? - Answers -Mean, median, and mode
What are the five number categories? - Answers -Median, mean, mode, minimum,
maximum
What are the measures of variability? - Answers -1st and 3rd quartiles
How do you find quartile 1? - Answers -Quartile 1
-median of the observations whose positions are ordered list are to the left of the overall
median
How do you find quartile 3? - Answers -Median of the observations whose positions in
the ordered list are to the right of overall median
What percentage of observations lie below the 3rd quartile? - Answers -75%
