Question

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According to a recent survey the mean monthly cell phone for Canadians is $68.72. Suppose monthly cell phone bills are normally distributed with a standard deviation of $8.46. What is the probability that a randomly selected cell phone bill is between $60 and $70? Q 0.55% 0 0.1515 0 0.4081 0 0.4042

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Answer & Explanation
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answer = 0.4081

Step-by-step explanation

we have that μ=68.72  and σ=8.46

z=σxμ   hence

P(60<x<70)=P(8.466068.72<z<8.467068.72)

=P(-1.03< z < 0.15)

=P(z <0.15) - P(z <  -1.03)

Now from  z table

=0.5596 - 0.1515

= 0.4081