n 100 random samples of water from a fresh water lake were t

n =100 random samples of water from a fresh water lake were taken and the calcium concentration (milligrams per liter) measured. A 95% Cl on the mean calcium concentration is 0.49

Solution

a)

It would be LONGER.

Greater confidence levels yield longer confidence intervals.

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b)

This is INCORRECT.

The mean is only either inside or outside it; there are no chances.

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c)

This is INCORRECT.

On the average, 950 will contain the true value of u. But not always. You would expect it to be AROUND 950, but not always 950.