Edexcel A Level Maths- Statistics Questions & Answers 22024/2025

Edexcel A Level Maths- Statistics Questions & Answers 22024/2025 Linear Regression - ANS-y = axⁿ logy = loga + nlogx Exponential Regression - ANS-y = ab^x logy = loga + xlogb Normal Approximation - ANS-µ = np σ =√(np(1-p)) Mean - ANS-∑x ÷ n GF: ∑xf ÷ ∑f Variance - ANS-(∑x²/n) - (∑x/n)² Standard Deviation - ANS-√variance Histograms: Height - ANS-Area = k x frequency Frequency Density - ANS-frequency ÷ class width Population - ANS-Whole set of items of interest. Census - ANS-Observes/measures every member of a population Sample - ANS-Selection of observations taken from a subset of the population which is used to find out info about the population. Sampling Frame - ANS-A list of individuals (named or numbered) from whom the sample is drawn Random Sampling - ANS-Every member of the population has an equal chance of being selected Systematic Sampling - ANS-Every nth person is chosen. Stratified Sampling - ANS-Population is divided into mutually exclusive Strat and a random sample is taken from each. Quota Sampling - ANS-Interviewer selects a sample that reflects the characteristics of the population Opportunity Sampling - ANS-Choosing whoever is available Continuous Variable - ANS-Can take any value in a given range Discrete Variable - ANS-Takes specific values in a given range Conditions for Binomial - ANS-Fixed no. of trials 2 possible outcomes Outcomes are independent Fixed probability of success Probability: Independent if... - ANS-P(A∩B) = P(A) X P(B) P(A|B) = P(A) Probability: Mutually exclusive if... - ANS-P(A∩B) = 0 P(A∪B) = P(A) + P(B) Conditional Probability - ANS-P(A|B) = P(A∩B)/P(B) Probability Addition Rule - ANS-P(A∪B) = P(A) + P(B) - P(A∩B) If there are 3 events, and A and B are mutually exclusive... - ANS-P(A∪B∪C) = P(A) + P(B) + P(C) - P(A∩C) - P(B∩C) What is a DRV - discrete random variable - ANS-it is a random variable that can only take certain values ... - ANS-... probability mass function - ANS-a function that gives the probability that a discrete random variable is exactly equal to some value what does a probability distribution do - ANS-describes the probability of any outcome in the sample space P(A/B) = - ANS-(P(A n B)) --------------- P(B) If they are independent events P(A) * P(B) = - ANS-P(A N B) SUM OF P(X=x) = - ANS-1 formula for probability X=r where X is the number of desired outcomes binomial distribution formula - ANS-nCr P^r * (1-p)^(n-r) p = probability of success r = number of times you want success n= number of trials standard deviation - ANS-a computed measure of how much scores vary around the mean score general probability addition rule - ANS-P(A∪B)=P(A)+P(B)−P(A∩B) P(A∩B)=P(A)+P(B)−P(A∪B) what is an event - ANS-a set of possible outcomes - not necessarily equally likely sample space - ANS-set of all possible outcomes, all equally likely A ∪ B - ANS-means A or B or both A ∩ B - ANS-means both A and B The rules for tree diagrams are - ANS-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). Continues...