Question

The heights of dogs, in inches, in a city have an unknown distribution with mean 22 and standard deviation 3 inches. A sample, with size n=39, is randomly drawn from the population and the mean is taken. What is the probability that the mean is less than 21.7 inches?

z 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09

−0.7 0.2420 0.2389 0.2358 0.2327 0.2296 0.2266 0.2236 0.2206 0.2177 0.2148

−0.6 0.2743 0.2709 0.2676 0.2643 0.2611 0.2578 0.2546 0.2514 0.2483 0.2451

−0.5 0.3085 0.3050 0.3015 0.2981 0.2946 0.2912 0.2877 0.2843 0.2810 0.2776

−0.4 0.3446 0.3409 0.3372 0.3336 0.3300 0.3264 0.3228 0.3192 0.3156 0.3121

You may use a calculator or the portion of the z-table given above. Round the final answer to four decimal places.

Answer 1

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