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Probability · Part 2 of 2
6 exam-style questions with model answers, plus 6 quick multi-choice questions — every question on this part of the standard, grouped by the 2 pages of notes they come from.
Write a full answer before you reveal the model one. That comparison is where the learning happens.
A normal distribution has mean 50 and standard deviation 10. Find the z-score of the value 65.
Test scores are normally distributed with mean 60 and standard deviation 12. Find the probability that a randomly chosen score is less than 78.
The weights of bags of flour are normally distributed with mean 1000 g and standard deviation 15 g. The heaviest 5% are set aside. Find the minimum weight for a bag to be set aside.
A spinner is spun 50 times and lands on red 20 times. Find the experimental probability of red.
A coin is tossed 40 times and shows heads 24 times. Compare the experimental probability of heads with the theoretical value.
Explain how you could use random digits (0–9) to simulate whether each of 5 buses is on time, given that a bus is on time 70% of the time, and describe how to estimate the probability that all 5 are on time.