STAT 100 Exam #1 UPDATED ACTUAL
Questions and CORRECT Answers
Variable - CORRECT ANSWER Particular characteristic of the individual (member of the
population)
Sample - CORRECT ANSWER Subset of the population for which data are collected. Must be
representative of the population.
Quantitative Variable - CORRECT ANSWER A variable that takes numerical values, and the
values represent a measurement using a numerical scale.
Qualitative (Categorical) Variable - CORRECT ANSWER A variable that allows for classification
of individuals based on some attribute or characteristic. Qualitative variables take category or label
values, and place an individual into a group or category.
Measure of Central Tendency - CORRECT ANSWER Can be interpreted as a typical value or
expected value of a variable.
Mode - CORRECT ANSWER The value that occurs the most often.
Mean - CORRECT ANSWER The average of all observations. Very sensitive to extreme values
outliers.
Median - CORRECT ANSWER The middle value of a distribution. Resistant to extreme values of
outliers.
Right Skewed Distributions - CORRECT ANSWER Mean > Median
Left Skewed Distributions - CORRECT ANSWER Median > Mean
, Symmetric - CORRECT ANSWER Mean roughly equals the median.
Measure of Dispersion - CORRECT ANSWER Quantifies how spread out data points are around a
central value.
1. Range
2. IQR
3. Standard Deviation
Range - CORRECT ANSWER Difference between the minimum value and maximum value.
IQR - CORRECT ANSWER The quartile of the distribution of a variable divide the ordered
observations (smallest to largest) into 4 equal sized groups.
IQR = Q3-Q1
Quartiles - CORRECT ANSWER 1. 25% observations below Q1
2. 50% observations below Q2
3. 75% observations below Q3
Standard Deviation - CORRECT ANSWER Gives the average (or typical distance) between a
randomly selected observation & the mean of the distribution/variable.
Smaller SD -> less variability
Larger SD -> more variability
Explanatory Variable - CORRECT ANSWER The variable that's assumed to explain, predict, or
affect the response variable.
Response Variable - CORRECT ANSWER The variable that's assumed to respond to the
explanatory variable; usually the outcome of interest.
Questions and CORRECT Answers
Variable - CORRECT ANSWER Particular characteristic of the individual (member of the
population)
Sample - CORRECT ANSWER Subset of the population for which data are collected. Must be
representative of the population.
Quantitative Variable - CORRECT ANSWER A variable that takes numerical values, and the
values represent a measurement using a numerical scale.
Qualitative (Categorical) Variable - CORRECT ANSWER A variable that allows for classification
of individuals based on some attribute or characteristic. Qualitative variables take category or label
values, and place an individual into a group or category.
Measure of Central Tendency - CORRECT ANSWER Can be interpreted as a typical value or
expected value of a variable.
Mode - CORRECT ANSWER The value that occurs the most often.
Mean - CORRECT ANSWER The average of all observations. Very sensitive to extreme values
outliers.
Median - CORRECT ANSWER The middle value of a distribution. Resistant to extreme values of
outliers.
Right Skewed Distributions - CORRECT ANSWER Mean > Median
Left Skewed Distributions - CORRECT ANSWER Median > Mean
, Symmetric - CORRECT ANSWER Mean roughly equals the median.
Measure of Dispersion - CORRECT ANSWER Quantifies how spread out data points are around a
central value.
1. Range
2. IQR
3. Standard Deviation
Range - CORRECT ANSWER Difference between the minimum value and maximum value.
IQR - CORRECT ANSWER The quartile of the distribution of a variable divide the ordered
observations (smallest to largest) into 4 equal sized groups.
IQR = Q3-Q1
Quartiles - CORRECT ANSWER 1. 25% observations below Q1
2. 50% observations below Q2
3. 75% observations below Q3
Standard Deviation - CORRECT ANSWER Gives the average (or typical distance) between a
randomly selected observation & the mean of the distribution/variable.
Smaller SD -> less variability
Larger SD -> more variability
Explanatory Variable - CORRECT ANSWER The variable that's assumed to explain, predict, or
affect the response variable.
Response Variable - CORRECT ANSWER The variable that's assumed to respond to the
explanatory variable; usually the outcome of interest.
