Analysis and Approaches for IBDP Maths Ebook 1 | Page 274

Your Practice Set – Analysis and Approaches for IBDP Mathematics
2. In a school the probability that a student is left handed is 0.12. A sample of 135 students
is randomly selected from the school.
(a)
(b)
(c)
Find the expected number of left-handed students in this sample.
Find the probability that exactly 20 students are left handed.
Find the probability that more than 16 students are left handed.
[2]
[2]
[3]
3. A factory makes lamps. The probability that a lamp is defective is 0.02. The factory tests
a random sample of 50 lamps.
(a)
(b)
(c)
Find the mean number of defective lamps in the sample.
Find the probability that there are exactly nine defective lamps in the sample.
Find the probability that there is at most two defective lamps in the
sample.
[2]
[2]
[3]
4. The probability of obtaining heads on a biased coin is 0.69. The coin is tossed nine times.
(a)
(b)
(c)
Find the mean number of heads.
Find the probability of obtaining exactly six heads.
Find the probability of obtaining less than three heads.
[2]
[2]
[3]
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