AP Statistics Exam Questions and Answers Verified Solutions Latest Update
(2026/2027) Already Graded A+
How do you check if there is outliers? - (answer)calculate IQR; anything above Q3+1.5(IQR) or below Q1-
1.5(IQR) is an outlier
If a graph is skewed, should we calculate the median or the mean? Why? - (answer)median; it is resistant
to skews and outliers
If a graph is roughly symmetrical, should we calculate the median or the mean? Why? - (answer)mean;
generally is more accurate if the data has no outliers
What is in the five number summary? - (answer)Minimum, Q1, Median, Q3, Maximum
Relationship between variance and standard deviation? - (answer)variance=(standard deviation)^2
variance definition - (answer)the variance is roughly the average of the squared differences between
each observation and the mean
standard deviation - (answer)the standard deviation is the square root of the variance
What should we use to measure spread if the median was calculated? - (answer)IQR
What should we use to measure spread if the mean was calculated? - (answer)standard deviation
What is the IQR? How much of the data does it represent? - (answer)Q3-Q1; 50%
How do you calculate standard deviation? - (answer)1. Type data into L1
2. Find mean with 1 Variable Stats
3. Turn L2 into (L1-mean)
4. Turn L3 into (L2)^2
5. Go to 2nd STAT over to MATH, select sum(
,AP Statistics Exam Questions and Answers Verified Solutions Latest Update
(2026/2027) Already Graded A+
6. Type in L3
7. multiply it by (1/n-1)
8. Square root it
What is the formula for standard deviation? - (answer)
Categorical variables vs. Quantitative Variables - (answer)Categorical: individuals can be assigned to one
of several groups or categories
Quantitative: takes numberical values
If a possible outlier is on the fence, is it an outlier? - (answer)No
Things to include when describing a distribution - (answer)Center (Mean or Median), Unusual Gaps or
Outliers, Spread (Standard Deviation or IQR), Shape (Roughly Symmetric, slightly/heavily skewed left or
right, bimodal, range)
Explain how to standardize a variable. What is the purpose of standardizing a variable? -
(answer)Subtract the distribution mean and then divide by standard deviation. Tells us how many
standard deviations from the mean an observation falls, and in what direction.
What effect does standardizing the values have on the distribution? - (answer)shape would be the same
as the original distribution, the mean would become 0, the standard deviation would become 1
What is a density curve? - (answer)a curve that (a) is on or above the horizontal axis, and (b) has exactly
an area of 1
Inverse Norm - (answer)when you want to find the percentile: invNorm (area, mean, standard deviation)
z - (answer)(x-mean)/standard deviation
, AP Statistics Exam Questions and Answers Verified Solutions Latest Update
(2026/2027) Already Graded A+
pth percentile - (answer)the value with p percent observations less than is
cumulative relative frequency graph - (answer)can be used to describe the position of an individual
within a distribution or to locate a specified percentile of the distribution
How to find and interpret the correlation coefficient r for a scatterplot - (answer)STAT plot, scatter, L1
and L2 (Plot 1: ON); STAT --> CALC --> 8:LinReg(a+bx)
No r? --> 2nd 0 (Catalog) down to Diagnostic ON
r - (answer)tells us the strength of a LINEAR association. -1 to 1. Not resistant to outliers
r^2 - (answer)the proportion (percent) of the variation in the values of y that can be accounted for by
the least squares regression line
residual plot - (answer)a scatterplot of the residuals against the explanatory variable. Residual plots help
us assess how well a regression line fits the data. It should have NO PATTERN
regression line - (answer)a line that describes how a response variable y changes as an explanatory
variable x changes. We often use a regression line to predict the value of y for a given value of x.
residual formula - (answer)residual=y-y(hat) aka observed y - predicted y
What method do you use to check if a distribution or probability is binomial? - (answer)BINS:
1. Binary: There only two outcomes (success and failure)
2. Independent: The events independent of one another?
3. Number: There is a fixed number of trials
4. Success: The probability of success equal in each trial
What method do you use to check if a distribution or probability is geometric? - (answer)BITS:
(2026/2027) Already Graded A+
How do you check if there is outliers? - (answer)calculate IQR; anything above Q3+1.5(IQR) or below Q1-
1.5(IQR) is an outlier
If a graph is skewed, should we calculate the median or the mean? Why? - (answer)median; it is resistant
to skews and outliers
If a graph is roughly symmetrical, should we calculate the median or the mean? Why? - (answer)mean;
generally is more accurate if the data has no outliers
What is in the five number summary? - (answer)Minimum, Q1, Median, Q3, Maximum
Relationship between variance and standard deviation? - (answer)variance=(standard deviation)^2
variance definition - (answer)the variance is roughly the average of the squared differences between
each observation and the mean
standard deviation - (answer)the standard deviation is the square root of the variance
What should we use to measure spread if the median was calculated? - (answer)IQR
What should we use to measure spread if the mean was calculated? - (answer)standard deviation
What is the IQR? How much of the data does it represent? - (answer)Q3-Q1; 50%
How do you calculate standard deviation? - (answer)1. Type data into L1
2. Find mean with 1 Variable Stats
3. Turn L2 into (L1-mean)
4. Turn L3 into (L2)^2
5. Go to 2nd STAT over to MATH, select sum(
,AP Statistics Exam Questions and Answers Verified Solutions Latest Update
(2026/2027) Already Graded A+
6. Type in L3
7. multiply it by (1/n-1)
8. Square root it
What is the formula for standard deviation? - (answer)
Categorical variables vs. Quantitative Variables - (answer)Categorical: individuals can be assigned to one
of several groups or categories
Quantitative: takes numberical values
If a possible outlier is on the fence, is it an outlier? - (answer)No
Things to include when describing a distribution - (answer)Center (Mean or Median), Unusual Gaps or
Outliers, Spread (Standard Deviation or IQR), Shape (Roughly Symmetric, slightly/heavily skewed left or
right, bimodal, range)
Explain how to standardize a variable. What is the purpose of standardizing a variable? -
(answer)Subtract the distribution mean and then divide by standard deviation. Tells us how many
standard deviations from the mean an observation falls, and in what direction.
What effect does standardizing the values have on the distribution? - (answer)shape would be the same
as the original distribution, the mean would become 0, the standard deviation would become 1
What is a density curve? - (answer)a curve that (a) is on or above the horizontal axis, and (b) has exactly
an area of 1
Inverse Norm - (answer)when you want to find the percentile: invNorm (area, mean, standard deviation)
z - (answer)(x-mean)/standard deviation
, AP Statistics Exam Questions and Answers Verified Solutions Latest Update
(2026/2027) Already Graded A+
pth percentile - (answer)the value with p percent observations less than is
cumulative relative frequency graph - (answer)can be used to describe the position of an individual
within a distribution or to locate a specified percentile of the distribution
How to find and interpret the correlation coefficient r for a scatterplot - (answer)STAT plot, scatter, L1
and L2 (Plot 1: ON); STAT --> CALC --> 8:LinReg(a+bx)
No r? --> 2nd 0 (Catalog) down to Diagnostic ON
r - (answer)tells us the strength of a LINEAR association. -1 to 1. Not resistant to outliers
r^2 - (answer)the proportion (percent) of the variation in the values of y that can be accounted for by
the least squares regression line
residual plot - (answer)a scatterplot of the residuals against the explanatory variable. Residual plots help
us assess how well a regression line fits the data. It should have NO PATTERN
regression line - (answer)a line that describes how a response variable y changes as an explanatory
variable x changes. We often use a regression line to predict the value of y for a given value of x.
residual formula - (answer)residual=y-y(hat) aka observed y - predicted y
What method do you use to check if a distribution or probability is binomial? - (answer)BINS:
1. Binary: There only two outcomes (success and failure)
2. Independent: The events independent of one another?
3. Number: There is a fixed number of trials
4. Success: The probability of success equal in each trial
What method do you use to check if a distribution or probability is geometric? - (answer)BITS:
