The amount of time that a drive-through bank teller spends on a customer is a random variable with a mean μ = 3.2 minutes and a standard deviation σ = 1.6 minutes. If a random sample of 64 customers is observed, find the probability that their mean time at the teller's window is at least 3.3 minutes but less than 3.4 minutes.
Added by Carlos B.
Step 1
3 - 3.2}{1.6/\sqrt{64}} = \frac{0.1}{0.2} = 0.5\) \(z_{\text{upper}} = \frac{3.4 - 3.2}{1.6/\sqrt{64}} = \frac{0.2}{0.2} = 1.0\) Show more…
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The amount of time that a drive-through bank teller spends on a customer is a random variable with a mean $\mu=3.2$ minutes and a standard deviation $\sigma=1.6$ minutes. If a random sample of 64 customers is observed, find the probability that their mean time at the teller's counter is (a) at most 2.7 minutes: (b) more than 3.5 minutes; (c) at least 3.2 minutes but less than 3.4 minutes.
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The amount of time that a drive-through bank teller spends on a customer is a random variable with a mean μ=3.9 minutes and a standard deviation σ=1.6 minutes. If a random sample of 64 customers is observed, find the probability that their mean time at the teller's window is (a) at most 3.6 minutes; (b) more than 4.1 minutes; (c) at least 3.9 minutes but less than 4.3 minutes.
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