edexcel alevel january 2014 s1 paper
variable X has parameters n=10 and p=0.5. What is the probability that X is at least 7?" Approach: Students should recognize the need for calculating P(X ≥ 7) = P(X=7) + P(X=8) + P(X=9) + P(X=10), then use binomial probability formulas or tables. Tip: Fami