STATISTICS PORTAGE CNSL 503 EXAM SCRIPT 2025
QUESTIONS WITH ANSWERS RATED A+
✔✔How to calculate median when there is an odd number of scores? - ✔✔arrange
scores in ascending order and identify the middle value
✔✔How to calculate median when there is an even number of scores? - ✔✔arrange
scores in ascending order and take the average of the 2 middle values
✔✔Is the median affected by outliers? - ✔✔no
✔✔The median is preferred when... - ✔✔the distribution contains extreme scores or is
skewed or variables measured on an ordinal scale
✔✔mode - ✔✔the most common score in a dataset
✔✔The mode is most useful for.... - ✔✔variables measured on a nominal scale or to
describe the shape of a distribution (unimodal, bimodal, trimodal)
✔✔Use mean for... - ✔✔symmetric data
✔✔Use median for... - ✔✔skewed data
✔✔Use mode for... - ✔✔describing the peak
✔✔variability - ✔✔describes the spread of the distribution
✔✔measures of variability - ✔✔range, interquartile range, sum of squares, variance,
standard deviation
✔✔The range and interquartile range are based on... - ✔✔only 2 scores
✔✔The sum of squares, variance and standard deviation are based on... - ✔✔all the
scores related to one another
✔✔range - ✔✔the difference between the highest value and the lowest value in a
dataset
✔✔The range is calculated by... - ✔✔subtracting the lowest value and the highest value
in a dataset
✔✔formula for range - ✔✔range= Xmax- Xmin
X=score
, ✔✔Is the range sensitive to outliers? - ✔✔yes
✔✔interquartile range (IQR) - ✔✔calculated by subtracting the lower quartile from the
upper quartile
✔✔quartiles - ✔✔values that divide a data set into four equal parts
✔✔formula for interquartile range - ✔✔IQR= Q3-Q1
✔✔lower quartile/first quartile (Q1) - ✔✔separates the lowest 1/4 of the data from the
upper 3/4 of data; the median of the lower half of data
✔✔middle quartile/second quartile (Q2) - ✔✔the overall median of the dataset
✔✔upper quartile/ third quartile (Q3) - ✔✔separates the highest 1/4 of the dataset from
the lowest 3/4 of the dataset; the median of the upper half of the score
✔✔Because the IQR only accounts for the middle 50% of the distribution, it is less
susceptible to influence by... - ✔✔outliers
✔✔box plot (box and wisker plot) - ✔✔graph the quartiles in a box and the minimum
and maximum values as "wiskers" extending outside the box
✔✔variability - ✔✔the average distance from the mean
✔✔standard deviation - ✔✔the average distance between each score and the mean
✔✔sum of squares (SS) - ✔✔sum of the squared deviations between each score and
the mean
✔✔formula for population SS - ✔✔SS=Σ(X-μ)^2
SS= sum of squares
Σ= sum up
X= score
X-μ= deviation between the score and the mean
✔✔formula for sample SS - ✔✔SS= Σ(X-x̅)^2
SS=sum of squares
Σ= sum up
x̅= sample mean
X=score
✔✔variance - ✔✔the average squared deviations between each score and the mean
QUESTIONS WITH ANSWERS RATED A+
✔✔How to calculate median when there is an odd number of scores? - ✔✔arrange
scores in ascending order and identify the middle value
✔✔How to calculate median when there is an even number of scores? - ✔✔arrange
scores in ascending order and take the average of the 2 middle values
✔✔Is the median affected by outliers? - ✔✔no
✔✔The median is preferred when... - ✔✔the distribution contains extreme scores or is
skewed or variables measured on an ordinal scale
✔✔mode - ✔✔the most common score in a dataset
✔✔The mode is most useful for.... - ✔✔variables measured on a nominal scale or to
describe the shape of a distribution (unimodal, bimodal, trimodal)
✔✔Use mean for... - ✔✔symmetric data
✔✔Use median for... - ✔✔skewed data
✔✔Use mode for... - ✔✔describing the peak
✔✔variability - ✔✔describes the spread of the distribution
✔✔measures of variability - ✔✔range, interquartile range, sum of squares, variance,
standard deviation
✔✔The range and interquartile range are based on... - ✔✔only 2 scores
✔✔The sum of squares, variance and standard deviation are based on... - ✔✔all the
scores related to one another
✔✔range - ✔✔the difference between the highest value and the lowest value in a
dataset
✔✔The range is calculated by... - ✔✔subtracting the lowest value and the highest value
in a dataset
✔✔formula for range - ✔✔range= Xmax- Xmin
X=score
, ✔✔Is the range sensitive to outliers? - ✔✔yes
✔✔interquartile range (IQR) - ✔✔calculated by subtracting the lower quartile from the
upper quartile
✔✔quartiles - ✔✔values that divide a data set into four equal parts
✔✔formula for interquartile range - ✔✔IQR= Q3-Q1
✔✔lower quartile/first quartile (Q1) - ✔✔separates the lowest 1/4 of the data from the
upper 3/4 of data; the median of the lower half of data
✔✔middle quartile/second quartile (Q2) - ✔✔the overall median of the dataset
✔✔upper quartile/ third quartile (Q3) - ✔✔separates the highest 1/4 of the dataset from
the lowest 3/4 of the dataset; the median of the upper half of the score
✔✔Because the IQR only accounts for the middle 50% of the distribution, it is less
susceptible to influence by... - ✔✔outliers
✔✔box plot (box and wisker plot) - ✔✔graph the quartiles in a box and the minimum
and maximum values as "wiskers" extending outside the box
✔✔variability - ✔✔the average distance from the mean
✔✔standard deviation - ✔✔the average distance between each score and the mean
✔✔sum of squares (SS) - ✔✔sum of the squared deviations between each score and
the mean
✔✔formula for population SS - ✔✔SS=Σ(X-μ)^2
SS= sum of squares
Σ= sum up
X= score
X-μ= deviation between the score and the mean
✔✔formula for sample SS - ✔✔SS= Σ(X-x̅)^2
SS=sum of squares
Σ= sum up
x̅= sample mean
X=score
✔✔variance - ✔✔the average squared deviations between each score and the mean
