4.5 Probability basicsIB Maths: Applications and Interpretation SL: Mind map

Exam questions on 4.5 Probability basics

1. A bag contains 5 red, 3 blue and 2 green counters. One counter is chosen at random.
   The counter is returned to the bag and the experiment is repeated 150 times. Find the expected number of times that a red counter is chosen.2 marks
2. A fair six-sided die is rolled once and a fair coin is tossed once.
   Find the probability of obtaining a number less than 3 and a tail.2 marks
3. A spinner has four equal-sized sectors numbered 1 to 4. It is spun 200 times and the results are: sector 1 occurs 38 times, sector 2 occurs 62 times, sector 3 occurs 55 times and sector 4 occurs 45 times.
   (i) Find the relative frequency of sector 2. (ii) Assuming that the spinner is fair, write down the theoretical probability of sector 2.3 marks