Download and practise with this ZIMSEC A-Level Statistics Paper 2 November 2021 question paper. Useful for exam revision, past paper practice, and preparation in Zimbabwe.
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This is the ZIMSEC A-Level Statistics question paper for Paper 2 from November 2021. Use it for exam practice under timed conditions.
2
Section A (40 marks)
Answer all questions in this section.
I When a school needs cleaning material, it calls one of the three companies $\mathrm{A}, \mathrm{B}$ or $\mathrm{C} .50 \%$ of the calls are to company $\mathrm{A}, 30 \%$ to company B whilst $20 \%$ are to Company C . The probability that a delivery is late from A is $4 \%$, from B is $6 \%$ and from C is $17 \%$ of the required time.
(a) Find the probability that the school calls for an order and it arrives late.
[3]
(b) Given that the school's order arrives late, find the conditional probability that it called company B.
[3]
2 A certain school has a total of 16 prefects, 8 boys and 8 girls. A committee of 6 prefects is to be chosen such that it has at least 4 boys and at least one girl.
(a) Find the number of possible ways of choosing the six prefects.
[4]
(b) Among the six prefects are 4 boys and 2 girls. When they are introduced during assembly they stand in a line. Find the number of ways in which the prefects should stand such that the girls are not next each other.
[3]
3 (a) State any three methods of collecting data
[3]
(b) A school uses one brand of light bulbs inside the buildings. The life times of a sample of 100 bulbs were recorded as follows
Time in months | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11
Number of bulbs | 16 | 21 | 17 | 14 | 12 | 5 | 5 | 4 | 3 | 2 | 1
(i) State median life time of a bulb.
[1]
(ii) Calculate the mean and variance of the life times of the bulbs.
[4]
4 A salesman sells a radio by calling potential customers The probability that any particular call achieves a sale is $\frac{1}{12}$, independently of all other calls. The salesman continues to make calls until one call achieves a sale.
(a) Name an appropriate distribution which models this situation.
[1]
(b) Calculate the probability that the call that achieves a sale
(i) is the fifth,
[2]
(ii) does not occur in the first five calls.
[2]
60462 N2021
scomened which corscomer.