2024 YIJC H1 Q6
2024 YIJC H1 Q6
4 marks
The battery lives of a new model of Something phones have a normal distribution. Based on the laboratory test results, \(15\)% of the phones have battery lives greater than \(20\) hours and \(40\)% of the phones have battery lives less than \(17\) hours.
Find the mean and variance of the distribution.[4]
Solution:
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Answer:Mean \(=17.6\) hours; variance \(=5.41\) hours² (3 s.f.).
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