STT 231 EXAM 1 COMPLETE
QUESTIONS WITH CORRECT
SLUTIONS||100% GUARANTEED
PASS||UPDATED 2026/2027
SYLLABUS||ALREADY GRADED A+||
what kind of statistic is the median said to be? (resistant or sensitive) - ANSWER
✓ resistant
Why is the median is said to be a resistant statistic? - ANSWER ✓ since it is
resistant or not affected by extreme observations
what kind of statistic is the mean said to be? (resistant or sensitive) - ANSWER ✓
sensitive
why is the mean is an example of a summary statistic which is sensitive or
nonresistant to extreme data values? - ANSWER ✓ the mean 𝑥 can be affected by
a single extreme observation
Because the mean is sensitive to extreme values and the median is resistant to
them, we can come up with a general rule-of-thumb for how the mean and median
behave when a distribution is skewed: - ANSWER ✓ the mean "follows the
skew/tail"
how to calculate interquartile range (IQR)? - ANSWER ✓ 75th percentile - 25th
percentile
what is the standard deviation of a data set? - ANSWER ✓ the approximate
average distance of the observational units from their common mean value
TRUE OR FALSE: often, a single data set is useful/valuable without knowing
how it relates to other observations of the same variable. - ANSWER ✓ false;
often a single data set is not useful/not valuable
, how many standard deviations something is from the mean - ANSWER ✓
standardized score (z-score)
What type of Skew does this exhibit? - ANSWER ✓ Right Skew, the tail is to the
right
What type of skew does this exhibit? - ANSWER ✓ Left Skew, the tail is to the
left
What type of skew does this exhibit - ANSWER ✓ Symmetrical
What type of Modality is this? - ANSWER ✓ Bimodal (two peaks)
Central Tendency - ANSWER ✓ Describes the balancing point of the data or a
typical value the variable described would take on
Outliers - ANSWER ✓ individual observations that differ markedly from the
pattern established by other observational units.
Granularity - ANSWER ✓ where values only at fixed intervals (measuring data
every 5 minutes, 1 minute, 2 minutes)
Mean - ANSWER ✓ The number that represents the numerical average value.
Median - ANSWER ✓ The number which divides the data in half. Half of the
measurements are smaller than the median, half are larger.
Density - ANSWER ✓ (# of observations)/(length of interval)
Do the mean and median have to be identical? - ANSWER ✓ No they do not have
to be identical
Resistant - ANSWER ✓ Median and IQR (is resistant or not affected by extreme
observations)
Sensitive - ANSWER ✓ Mean, Range, Standard Deviation (affected by a single
extreme observation)
, Symmetric data - ANSWER ✓ mean = median
Right Skewed Data - ANSWER ✓ mean is larger, median stays the same
(mean>median)
Left Skewed data - ANSWER ✓ mean is smaller, median stays the same
(mean<median)
What follows the tail of data? - ANSWER ✓ Mean
Range - ANSWER ✓ 100th percentile - 0th percentile (maximum - minimum)
IQR - ANSWER ✓ 75th percentile - 25th percentile (Q3-Q1)
Proportion - ANSWER ✓ special case of the mean applied to a simple categorical
variable. The categorical variable is deemed 1 = success or 0 = failures. Often
expressed as rates or proportions
Proportion Formula (pi^ or pi hat) - ANSWER ✓ (Number of success)/(Total
number of cases)
standard deviation - ANSWER ✓ approximate average distance of the
observational units from their common mean value
Standard Deviation Formula - ANSWER ✓ S = √(sum of squared deviations from
the mean)/(number of cases - 1)
Categorical Variable with success or failure S = - ANSWER ✓ the standard
deviation of the observations simplifies to be based on the sample proportion (pi
hat)
Independent - ANSWER ✓ If you change the value of one variable, the
distribution of the other variable does NOT change
Two ways variables play a role in a scientific study - ANSWER ✓ Explanatory,
Response
QUESTIONS WITH CORRECT
SLUTIONS||100% GUARANTEED
PASS||UPDATED 2026/2027
SYLLABUS||ALREADY GRADED A+||
what kind of statistic is the median said to be? (resistant or sensitive) - ANSWER
✓ resistant
Why is the median is said to be a resistant statistic? - ANSWER ✓ since it is
resistant or not affected by extreme observations
what kind of statistic is the mean said to be? (resistant or sensitive) - ANSWER ✓
sensitive
why is the mean is an example of a summary statistic which is sensitive or
nonresistant to extreme data values? - ANSWER ✓ the mean 𝑥 can be affected by
a single extreme observation
Because the mean is sensitive to extreme values and the median is resistant to
them, we can come up with a general rule-of-thumb for how the mean and median
behave when a distribution is skewed: - ANSWER ✓ the mean "follows the
skew/tail"
how to calculate interquartile range (IQR)? - ANSWER ✓ 75th percentile - 25th
percentile
what is the standard deviation of a data set? - ANSWER ✓ the approximate
average distance of the observational units from their common mean value
TRUE OR FALSE: often, a single data set is useful/valuable without knowing
how it relates to other observations of the same variable. - ANSWER ✓ false;
often a single data set is not useful/not valuable
, how many standard deviations something is from the mean - ANSWER ✓
standardized score (z-score)
What type of Skew does this exhibit? - ANSWER ✓ Right Skew, the tail is to the
right
What type of skew does this exhibit? - ANSWER ✓ Left Skew, the tail is to the
left
What type of skew does this exhibit - ANSWER ✓ Symmetrical
What type of Modality is this? - ANSWER ✓ Bimodal (two peaks)
Central Tendency - ANSWER ✓ Describes the balancing point of the data or a
typical value the variable described would take on
Outliers - ANSWER ✓ individual observations that differ markedly from the
pattern established by other observational units.
Granularity - ANSWER ✓ where values only at fixed intervals (measuring data
every 5 minutes, 1 minute, 2 minutes)
Mean - ANSWER ✓ The number that represents the numerical average value.
Median - ANSWER ✓ The number which divides the data in half. Half of the
measurements are smaller than the median, half are larger.
Density - ANSWER ✓ (# of observations)/(length of interval)
Do the mean and median have to be identical? - ANSWER ✓ No they do not have
to be identical
Resistant - ANSWER ✓ Median and IQR (is resistant or not affected by extreme
observations)
Sensitive - ANSWER ✓ Mean, Range, Standard Deviation (affected by a single
extreme observation)
, Symmetric data - ANSWER ✓ mean = median
Right Skewed Data - ANSWER ✓ mean is larger, median stays the same
(mean>median)
Left Skewed data - ANSWER ✓ mean is smaller, median stays the same
(mean<median)
What follows the tail of data? - ANSWER ✓ Mean
Range - ANSWER ✓ 100th percentile - 0th percentile (maximum - minimum)
IQR - ANSWER ✓ 75th percentile - 25th percentile (Q3-Q1)
Proportion - ANSWER ✓ special case of the mean applied to a simple categorical
variable. The categorical variable is deemed 1 = success or 0 = failures. Often
expressed as rates or proportions
Proportion Formula (pi^ or pi hat) - ANSWER ✓ (Number of success)/(Total
number of cases)
standard deviation - ANSWER ✓ approximate average distance of the
observational units from their common mean value
Standard Deviation Formula - ANSWER ✓ S = √(sum of squared deviations from
the mean)/(number of cases - 1)
Categorical Variable with success or failure S = - ANSWER ✓ the standard
deviation of the observations simplifies to be based on the sample proportion (pi
hat)
Independent - ANSWER ✓ If you change the value of one variable, the
distribution of the other variable does NOT change
Two ways variables play a role in a scientific study - ANSWER ✓ Explanatory,
Response
