The average time a subscriber of a local newspaper The News spends reading it is 24...

The average time a subscriber of a local newspaper The News spends reading it is 24 minutes. Assume that the times are normally distributed and the standard deviation is 10 minutes.

(a) Compute the probability that a subscriber spends more than 30 minutes reading the paper. (b) Find the range of reading times for the middle 90% of the subscribers.

[Hint: First, find zc such that P(−zc < z < zc) = 0.90.]

(c) The average time was calculated from a sample of 20 subscribers. Compute the probability that this mean value is more than 30 minutes.

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Expert Solution

orchestra answered 1 year ago

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