Math 120 Statistics Introductory Certification Paper 2026 Accurate Solutions Graded A+

MATH 120 STATISTICS
INTRODUCTORY CERTIFICATION
PAPER 2026 ACCURATE SOLUTIONS
GRADED A+

◉ Graphical summary: quantitative variable. Answer: Histograms and
box plots


◉ Numerical summaries: categorical variable. Answer: Tabulations
(frequency distribution), mode


◉ Numerical summaries: quantitative variable. Answer: Measures of
center (mean, median), measures of spread (SD, IQR), describing
shape (skewness, detecting outliers, 5 number summary)


◉ Quantitative variables can either be.... Answer: discrete or
continuous


◉ Distribution of a variable. Answer: Describes the different values a
variable takes and how frequently these values occur


◉ Goal for categorical variable. Answer: To describe the proportion
of individuals observed for each value of the variable

, ◉ Goal for quantitative variable. Answer: To describe the 'shape',
'center', and 'spread' of the distribution


◉ 2 measures of spread for quantitative variables. Answer: 1.
Variance and standard deviation (SD)
-Measure spread about the mean
-Most often used, but also sensitive to large values


2. Quartiles and percentiles
-Median
-Other percentiles


◉ IQR (Inter Quartile Range). Answer: The distance between the first
and third quartiles


◉ Right-skewed distribution. Answer: Mean is larger than the
median


◉ Symmetric distribution. Answer: Mean and median are the same


◉ left-skewed distribution. Answer: Mean is less than the median


◉ Five number summary. Answer: Min, Q1, Median, Q3, Max