Problem

Heights of fourth-graders are normally distributed with a mean of 52 inches and a standard deviation of 3.5 inches. Find the probability that a randomly selected fourth-grader is taller than 53 inches. $38.8 \%$ $42.7 \%$ $19.2 \%$ $40.1 \%$

Solution

Step 1 :The problem is asking for the probability that a randomly selected fourth-grader is taller than 53 inches. This is a problem of normal distribution. We know that the mean height is 52 inches and the standard deviation is 3.5 inches.

Step 2 :We need to find the z-score for 53 inches and then find the probability associated with that z-score. The z-score is calculated as \((X - μ) / σ\), where X is the value we're interested in, μ is the mean, and σ is the standard deviation.

Step 3 :Substituting the given values into the z-score formula, we get \(z = (53 - 52) / 3.5 = 0.2857142857142857\).

Step 4 :After finding the z-score, we can use a z-table or a function to find the probability. The probability associated with this z-score is approximately 0.3875 or 38.75%.

Step 5 :Final Answer: The probability that a randomly selected fourth-grader is taller than 53 inches is approximately \(\boxed{38.8\%}\).

From Solvely APP
Source: https://solvelyapp.com/problems/10258/

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