The discrete random variable X X\,X has the distribution X∼B(20,0.41)X \sim B(20, 0.41)X∼B(20,0.41).
Find P(3<X≤7)P(3 < X \le 7)P(3<X≤7).
A restaurant's records show that 30% of its customers order a starter. On one day a random sample of 50 customers is taken, and 9 of them order a starter. Stating your hypotheses clearly, test at the 5% significance level whether the proportion of customers ordering a starter has decreased.
40 exam-style questions on WJEC A Level Maths 2.5 Statistical hypothesis testing, covering 2.5.1 Statistical hypothesis testing, 2.5.2 Statistical hypothesis testing, 2.5.3 Statistical hypothesis testing, 2.5.4 Statistical hypothesis testing, and 2.5 Statistical hypothesis testing. Each one has a worked solution and a mark scheme showing where the marks go.