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IB Mathematics: Applications and Interpretation SL · 13.2: Probability Distributions · 13.2.11
Probability distributions: exam review Exam review: second paper Answers
Section A: short questions
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- (a) 0.15
- (b) 0.55
- (c) 5/16 (0.312)
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- (a) 0.1
- (b) 7/9 (0.778)
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- (a) \$3.50
- (b) −\$1.50; not fair
- (c) \$3.50
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- (a) x = 0: 7/15 (0.467); x = 1: 7/15 (0.467); x = 2: 1/15 (0.0667)
- (b) 3/5 (0.6)
- (c) 8/15 (0.533)
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- (a) X ~ B(15, 0.12)
- (b) 0.170
- (c) 0.974
- (d) 0.0959
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- (a) E(X) = 15, Var(X) = 6
- (b) p = 0.25, n = 80
- (c) 0.440
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- (a) Answers are independent; the probability of a correct guess is the same for every question
- (b) 0.0726
- (c) 0.208
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- (a) 0.367
- (b) 76
- (c) 84
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- (a) 83.85%
- (b) 0.0668
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- (a) 109 mm to 131 mm
- (b) lower quartile 114 mm, upper quartile 126 mm
- (c) \(\mu = 118\), \(\sigma = 11.2\)
Section B: long questions
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- (a) 0.159
- (b) 0.611
- (c) 28.0
- (d) 13.7
- (e) 0.186
- (f) The items are independent of each other, and the probability is the same for each
- (g) Mean 6 is less than 2 × 4 = 8, so the model gives a large probability of a negative value
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- (a) a + b = 0.55
- (b) a = 0.25, b = 0.3
- (c) 11/16 (0.688)
- (d) Expected profit −\$0.40; not fair
- (e) 0.146
- (f) 0.756
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- (a) The median is near the middle of the box; the whiskers are about the same length (symmetric)
- (b) Q1 = 34.0, Q3 = 42.0
- (c) 8.09
- (d) 46.4
- (e) 44.2
- (f) 5.88
jmaths.xyz · AI SL · 13.2.11 Unit review