Step 1 :Given the population mean (\(\mu\)) is 15 inches, the population standard deviation (\(\sigma\)) is 2 inches, and the sample size (\(n\)) is 48 fish. We want to find the probability that the sample mean (\(\bar{x}\)) is within 0.5 inch of the population mean.
Step 2 :First, calculate the standard deviation of the sample mean, also known as the standard error (SE). The formula for the standard error is: \(SE = \frac{\sigma}{\sqrt{n}}\)
Step 3 :Substitute the given values into the formula: \(SE = \frac{2}{\sqrt{48}} \approx 0.289\)
Step 4 :Next, calculate the z-scores for the boundaries of the interval around the population mean. The formula for a z-score is: \(z = \frac{\bar{x} - \mu}{SE}\)
Step 5 :For the lower boundary (14.5 inches), calculate the z-score: \(z_1 = \frac{14.5 - 15}{0.289} \approx -1.73\)
Step 6 :For the upper boundary (15.5 inches), calculate the z-score: \(z_2 = \frac{15.5 - 15}{0.289} \approx 1.73\)
Step 7 :Finally, find the probability that the z-score is between -1.73 and 1.73. This can be found using a standard normal distribution table or a calculator with a normal distribution function. The probability corresponds to the area under the standard normal curve between these two z-scores.
Step 8 :The probability is: \(P(-1.73 < Z < 1.73) \approx 0.9164\)
Step 9 :So, the probability that the sample mean is within 0.5 inch of the population mean is approximately 0.9164, or 91.64% when rounded to four decimal places.
Step 10 :The final answer is \(\boxed{0.9164}\)