DATA DRIVEN DECISION MAKING FINAL
CERTIFICATION TEST 2026 COMPREHENSIVE
STUDY GUIDE
◉ 68.2% of a sample will be within _______ standard deviation of the
mean. Answer: 1
◉ 95.4% of a sample will be within ______ standard deviations of the
mean. Answer: 2
◉ 99.7% of a sample will be within _____ standard deviations of the
mean. Answer: 3
◉ The mean is 20 and the standard deviation is 2, what is the
probability of being between 14 and 26 Answer: 99.7% (of the
sample will be within 3 standard deviations of the mean) 20 + 2 + 2
+ 2 = 26 and 20 - 2 - 2 - 2 = 14
◉ _______ can be used to differentiate between two samples with the
same mean. Answer: Variation
,◉ Which measurement can tell us where a single data point is on the
bell curve? Answer: z-score. (Tip: Remember z for me. Where are
you in the curve of your peers)
◉ You want to know how your height compares to all of your family
tree. How do you calculate a z score? Answer: (Your height - the
mean of the family tree height) divided by the standard deviation of
the family tree height (me-mean)/standard deviaiton
◉ You are 63" tall and the family tree averages 67" with a standard
deviation of 2". What is your z-score? Answer: (63-67)/2 = -2 You
are 2 standard deviations shorter than the family tree.
◉ Which measure lets you measure your height compared to your
maternal family tree and your height compared to your paternal
family tree? Answer: z-scores let us measure two samples by putting
them to the same scale.
◉ There are four shopping carts available and one has a broken
wheel. What is your probability of selecting the cart with the broken
wheel? Answer: 25% (1/4 = 0.25)
◉ There is a 20% of parking close to the door and a 30% chance of
getting the shopping cart with a squeaky wheel. How do we
calculated the probability of both events occurring? Answer:
Multiply Key Words: AND, ALL, BOTH
, ◉ There is a 20% of parking close to the door and a 30% chance of
getting the shopping cart with a squeaky wheel. How do we
calculated the probability of either event occurring? Answer:
Addition Key Words: OR, EITHER
◉ Multiplying two events calculates an ____________ Answer:
Intersection
◉ Adding two events calculates a _______________ Answer: Union
◉ The grocer is running a 10 for $10 special on cans of soup. You can
mix and match the 5 different flavors of soup. You decide to
purchase 10 cans. What can we use to count all the possible
outcomes of flavors picked? Answer: Combination
◉ There is a 90% chance you will have to wait in line for more than
6 minutes to check out at the grocer. What is the complement?
Answer: 10%. If there is a 90% chance of yes, then there is a 10%
chance of no. 90% + 10% = 100%
◉ 50% chance it will rain. There is a 20% chance you park in the
garage in the rain and a 60% chance you park there if it is not
raining. Given you are parked in the garage, what is the probability it
is raining? Which probability technique applies? Answer: Bayes
CERTIFICATION TEST 2026 COMPREHENSIVE
STUDY GUIDE
◉ 68.2% of a sample will be within _______ standard deviation of the
mean. Answer: 1
◉ 95.4% of a sample will be within ______ standard deviations of the
mean. Answer: 2
◉ 99.7% of a sample will be within _____ standard deviations of the
mean. Answer: 3
◉ The mean is 20 and the standard deviation is 2, what is the
probability of being between 14 and 26 Answer: 99.7% (of the
sample will be within 3 standard deviations of the mean) 20 + 2 + 2
+ 2 = 26 and 20 - 2 - 2 - 2 = 14
◉ _______ can be used to differentiate between two samples with the
same mean. Answer: Variation
,◉ Which measurement can tell us where a single data point is on the
bell curve? Answer: z-score. (Tip: Remember z for me. Where are
you in the curve of your peers)
◉ You want to know how your height compares to all of your family
tree. How do you calculate a z score? Answer: (Your height - the
mean of the family tree height) divided by the standard deviation of
the family tree height (me-mean)/standard deviaiton
◉ You are 63" tall and the family tree averages 67" with a standard
deviation of 2". What is your z-score? Answer: (63-67)/2 = -2 You
are 2 standard deviations shorter than the family tree.
◉ Which measure lets you measure your height compared to your
maternal family tree and your height compared to your paternal
family tree? Answer: z-scores let us measure two samples by putting
them to the same scale.
◉ There are four shopping carts available and one has a broken
wheel. What is your probability of selecting the cart with the broken
wheel? Answer: 25% (1/4 = 0.25)
◉ There is a 20% of parking close to the door and a 30% chance of
getting the shopping cart with a squeaky wheel. How do we
calculated the probability of both events occurring? Answer:
Multiply Key Words: AND, ALL, BOTH
, ◉ There is a 20% of parking close to the door and a 30% chance of
getting the shopping cart with a squeaky wheel. How do we
calculated the probability of either event occurring? Answer:
Addition Key Words: OR, EITHER
◉ Multiplying two events calculates an ____________ Answer:
Intersection
◉ Adding two events calculates a _______________ Answer: Union
◉ The grocer is running a 10 for $10 special on cans of soup. You can
mix and match the 5 different flavors of soup. You decide to
purchase 10 cans. What can we use to count all the possible
outcomes of flavors picked? Answer: Combination
◉ There is a 90% chance you will have to wait in line for more than
6 minutes to check out at the grocer. What is the complement?
Answer: 10%. If there is a 90% chance of yes, then there is a 10%
chance of no. 90% + 10% = 100%
◉ 50% chance it will rain. There is a 20% chance you park in the
garage in the rain and a 60% chance you park there if it is not
raining. Given you are parked in the garage, what is the probability it
is raining? Which probability technique applies? Answer: Bayes
