EDEXCEL A LEVEL STATISTICS PAPER 3 2026
PRACTICE QUESTIONS AND ANSWERS TOP
REVIEW A+
◉ The rules for tree diagrams are. Answer: Select which branches
you need
Multiply along each branch
Add the results of each branch needed.
Make sure that you include enough working to show which branches
you are using (method).
Be careful to allow for selection with and without replacement.
if you are told what has happened for the first choice and need to
find second you read off tree diagram
if you are told what has happened for the second choice use formula
◉ sample space diagram. Answer:
,◉ mutually exclusive events. Answer: Two events that cannot occur
at the same time
◉ what is P(A∩B) if two events are mutually exclusive. Answer:
P(A∩B) = 0
◉ Sampling units. Answer: Individual units of a population
◉ what does a census do. Answer: observes and measures every
member of a population
◉ advantages / disadvantages of census. Answer: advantages :
gives a completely accurate result
disadvantages
-time consuming and expensive
-hard to process large quantity of data
◉ advantages/disadvantages of a sample. Answer: advantages :
less time consuming and expensive than census
,fewer people have to respond
less data to process than in a census
disadvantages
data may not be as accurate
sample may not be large enough to give information about sub
groups of the population
◉ sampling frame. Answer: a list of individuals from whom the
sample is drawn
◉ population. Answer: a whole set of items that are of interest
◉ sample. Answer: a selection of observations taken from the subset
of the population which is used to find out information about the
population as a whole
◉ simple random sampling. Answer: Every sample from the
population has an equal chance of being chosen
- formed by when each item given number then random number
generator used or lottery
, ◉ simple random sampling advantages/disadvantages. Answer:
advantages
-easy and cheap to implement for small populations and small
samples
- free of bias
-each sample unit has a known and equal chance of selection
disadvantages
sampling frame is needed
not suitable when population size/sample size is large as it would be
potentially tie consuming, disruptive and expensive
◉ 3 different types of random sampling. Answer: Simple random
sampling
Systematic sampling
• Stratified sampling
PRACTICE QUESTIONS AND ANSWERS TOP
REVIEW A+
◉ The rules for tree diagrams are. Answer: Select which branches
you need
Multiply along each branch
Add the results of each branch needed.
Make sure that you include enough working to show which branches
you are using (method).
Be careful to allow for selection with and without replacement.
if you are told what has happened for the first choice and need to
find second you read off tree diagram
if you are told what has happened for the second choice use formula
◉ sample space diagram. Answer:
,◉ mutually exclusive events. Answer: Two events that cannot occur
at the same time
◉ what is P(A∩B) if two events are mutually exclusive. Answer:
P(A∩B) = 0
◉ Sampling units. Answer: Individual units of a population
◉ what does a census do. Answer: observes and measures every
member of a population
◉ advantages / disadvantages of census. Answer: advantages :
gives a completely accurate result
disadvantages
-time consuming and expensive
-hard to process large quantity of data
◉ advantages/disadvantages of a sample. Answer: advantages :
less time consuming and expensive than census
,fewer people have to respond
less data to process than in a census
disadvantages
data may not be as accurate
sample may not be large enough to give information about sub
groups of the population
◉ sampling frame. Answer: a list of individuals from whom the
sample is drawn
◉ population. Answer: a whole set of items that are of interest
◉ sample. Answer: a selection of observations taken from the subset
of the population which is used to find out information about the
population as a whole
◉ simple random sampling. Answer: Every sample from the
population has an equal chance of being chosen
- formed by when each item given number then random number
generator used or lottery
, ◉ simple random sampling advantages/disadvantages. Answer:
advantages
-easy and cheap to implement for small populations and small
samples
- free of bias
-each sample unit has a known and equal chance of selection
disadvantages
sampling frame is needed
not suitable when population size/sample size is large as it would be
potentially tie consuming, disruptive and expensive
◉ 3 different types of random sampling. Answer: Simple random
sampling
Systematic sampling
• Stratified sampling
