EDEXCEL A LEVEL STATISTICS PAPER 3 2026
COMPLETE STUDY GUIDE A+
◉ Exponential Regression. Answer: y = ab^x
logy = loga + xlogb
◉ Normal Approximation. Answer: µ = np
σ =√(np(1-p))
◉ Mean. Answer: ∑x ÷ n
GF: ∑xf ÷ ∑f
◉ Variance. Answer: (∑x²/n) - (∑x/n)²
◉ Standard Deviation. Answer: √variance
◉ Histograms: Height. Answer: Area = k x frequency
,◉ Frequency Density. Answer: frequency ÷ class width
◉ Population. Answer: Whole set of items of interest.
◉ Census. Answer: Observes/measures every member of a
population
◉ Sample. Answer: Selection of observations taken from a subset of
the population which is used to find out info about the population.
◉ Sampling Frame. Answer: A list of individuals (named or
numbered) from whom the sample is drawn
◉ Random Sampling. Answer: Every member of the population has
an equal chance of being selected
◉ Systematic Sampling. Answer: Every nth person is chosen.
◉ Stratified Sampling. Answer: Population is divided into mutually
exclusive Strat and a random sample is taken from each.
◉ Quota Sampling. Answer: Interviewer selects a sample that
reflects the characteristics of the population
,◉ Opportunity Sampling. Answer: Choosing whoever is available
◉ Continuous Variable. Answer: Can take any value in a given range
◉ Discrete Variable. Answer: Takes specific values in a given range
◉ Conditions for Binomial. Answer: Fixed no. of trials
2 possible outcomes
Outcomes are independent
Fixed probability of success
◉ Probability: Independent if.... Answer: P(A∩B) = P(A) X P(B)
P(A|B) = P(A)
◉ Probability: Mutually exclusive if.... Answer: P(A∩B) = 0
P(A∪B) = P(A) + P(B)
◉ Conditional Probability. Answer: P(A|B) = P(A∩B)/P(B)
, ◉ Probability Addition Rule. Answer: P(A∪B) = P(A) + P(B) - P(A∩B)
◉ If there are 3 events, and A and B are mutually exclusive....
Answer: P(A∪B∪C) = P(A) + P(B) + P(C) - P(A∩C) - P(B∩C)
◉ What is a DRV - discrete random variable. Answer: it is a random
variable that can only take certain values
◉ .... Answer: ...
◉ probability mass function. Answer: a function that gives the
probability that a discrete random variable is exactly equal to some
value
◉ what does a probability distribution do. Answer: describes the
probability of any outcome in the sample space
◉ P(A/B) =. Answer: (P(A n B))
---------------
P(B)
◉ If they are independent events P(A) * P(B) =. Answer: P(A N B)
COMPLETE STUDY GUIDE A+
◉ Exponential Regression. Answer: y = ab^x
logy = loga + xlogb
◉ Normal Approximation. Answer: µ = np
σ =√(np(1-p))
◉ Mean. Answer: ∑x ÷ n
GF: ∑xf ÷ ∑f
◉ Variance. Answer: (∑x²/n) - (∑x/n)²
◉ Standard Deviation. Answer: √variance
◉ Histograms: Height. Answer: Area = k x frequency
,◉ Frequency Density. Answer: frequency ÷ class width
◉ Population. Answer: Whole set of items of interest.
◉ Census. Answer: Observes/measures every member of a
population
◉ Sample. Answer: Selection of observations taken from a subset of
the population which is used to find out info about the population.
◉ Sampling Frame. Answer: A list of individuals (named or
numbered) from whom the sample is drawn
◉ Random Sampling. Answer: Every member of the population has
an equal chance of being selected
◉ Systematic Sampling. Answer: Every nth person is chosen.
◉ Stratified Sampling. Answer: Population is divided into mutually
exclusive Strat and a random sample is taken from each.
◉ Quota Sampling. Answer: Interviewer selects a sample that
reflects the characteristics of the population
,◉ Opportunity Sampling. Answer: Choosing whoever is available
◉ Continuous Variable. Answer: Can take any value in a given range
◉ Discrete Variable. Answer: Takes specific values in a given range
◉ Conditions for Binomial. Answer: Fixed no. of trials
2 possible outcomes
Outcomes are independent
Fixed probability of success
◉ Probability: Independent if.... Answer: P(A∩B) = P(A) X P(B)
P(A|B) = P(A)
◉ Probability: Mutually exclusive if.... Answer: P(A∩B) = 0
P(A∪B) = P(A) + P(B)
◉ Conditional Probability. Answer: P(A|B) = P(A∩B)/P(B)
, ◉ Probability Addition Rule. Answer: P(A∪B) = P(A) + P(B) - P(A∩B)
◉ If there are 3 events, and A and B are mutually exclusive....
Answer: P(A∪B∪C) = P(A) + P(B) + P(C) - P(A∩C) - P(B∩C)
◉ What is a DRV - discrete random variable. Answer: it is a random
variable that can only take certain values
◉ .... Answer: ...
◉ probability mass function. Answer: a function that gives the
probability that a discrete random variable is exactly equal to some
value
◉ what does a probability distribution do. Answer: describes the
probability of any outcome in the sample space
◉ P(A/B) =. Answer: (P(A n B))
---------------
P(B)
◉ If they are independent events P(A) * P(B) =. Answer: P(A N B)
