6 Figure 2 is a histogram showing the distribution of the time taken in minutes, by t, a group of people to swim 500 m. Figure 2 a Find the probability that a person chosen at random from the group takes longer than 18 minutes. (4 marks) b Estimate the probability that a person chosen at random from the group takes less than 30 minutes. (3 marks) A researcher measured the foot lengths of a random sample of ten-year-old 7 children. The lengths are summarised in the table below. Foot length, (cm) Number of children l, 10 < 12 5 l ⩽ 12 < 17 52 l ⩽ 17 < 19 30 l ⩽ 19 < 21 15 l ⩽ 21 < 23 11 l ⩽ 23 < 25 7 l ⩽ a Find the probability that a child chosen at random has a foot length less than 17 (3 marks) cm. b Find the probability that a child chosen at random has a foot length between 12 and State one assumption you have made. (3 marks) cm 18 cm.
6 Figure 2 is a histogram showing the distribution of the time taken in minutes, t, by a group of people to swim 500 m. Figure 2 a Find the probability that a person chosen at random from the group takes longer than 18 minutes. (4 marks) b Estimate the probability that a person chosen at random from the group takes less than 30 minutes. (3 marks) 7 A researcher measured the foot lengths of a random sample of ten-year-old children. The lengths are summarised in the table below. Foot length, l, (cm) Number of children 10 ⩽ l < 12 5 12 ⩽ l < 17 52 17 ⩽ l < 19 30 19 ⩽ l < 21 15 21 ⩽ l < 23 11 23 ⩽ l < 25 7 a Find the probability that a child chosen at random has a foot length less than 17 cm. (3 marks) b Find the probability that a child chosen at random has a foot length between 12 cm and 18 cm. State one assumption you have made. (3 marks)
19385_25-a-level-statistics-unit-3-test.docx