Paper 2 · normal distribution
Packets of washing powder have weights normally distributed with mean 2 kg and standard deviation 0,039 kg. What proportion of packets weigh more than 2,10 kg? Give your answer to 3 decimal places or as a percentage.
Model answer
0.005
Also accepted: 0.0052, 0.52%, 0.52 percent
Explanation: z = (2.10 - 2)/0.039, which is approximately 2.56, and P(Z > 2.56) is approximately 0.0052, so about 0.52% of packets weigh more than 2.10 kg.
Derived from ZIMSEC Statistics Paper 2, November 2022, Q2
