Number

2.4 Probability

1. There are 8 blue balls are in a bag, half as many red as blue and one white. What is the probability of picking a red ball?
$P(red) = 4 8+4+1 = 4 13$
2. Which has the higher probability?
1. Rolling a number size on a die or
2. Picking a red counter from a bag which has 7 blue, 8 yellow and 3 red counters?
The probability of rolling a six on a die is:
$P(6) = 1 6 = 0.1 6 ˙$
The probability of picking a red counter from a bag which has 7 blue, 8 yellow and 3 red counters is:
$P(red) = 3 7+8+3 = 3 18 = 0.1 6 ˙$
Both event have the same chance of occurring.
3. What is the meaning of independent events in probability and put it in context with an example.
Independent events mean that an event is not affected by a previous event. i.e. Each flip of a coin is independent because the coin doesn’t know what happened to it before.