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What is the probability that at least 70 use their phone at least once per hour?

User Zed Fang
by
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1 Answer

2 votes

Solution:

P(x₁ ≥ 70)

Z= (x-µ)/σ

µ = np

σ = √np(1-p)

P(x₁ ≥ 70) = p(x₁-np₁/√np₁ (1-p₁) > 70 – (150*0.51)/√150*0.51*0.49)

= p( z₁ ≥ -1.1433)

= 1-p (z₁ ≤ -1.1433)

= 1- 0.1265

= 0.8735

User Ivan Peevski
by
7.9k points

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