Paper 3 · June 2023 · Statistics: measurement scales, Poisson, chi-square, spatial autocorrelation
At a private clinic patients arrive at an average rate of 5 per hour, following a Poisson distribution. Calculate the probability that at most 3 patients arrive in a given hour, correct to 4 decimal places.
Model answer
0.2650
Also accepted: 0.265, 0.2650 (4 d.p.)
Explanation
P(X <= 3) = P(0) + P(1) + P(2) + P(3) = e^(-5)[1 + 5 + 12.5 + 20.8333] = 0.006738 x 39.3333 = 0.2650.
Derived from ZIMSEC Advanced Level Geography 6037/3 Paper 3 Practical Test, June 2023 session, Q1