Use the following to answer the questions below:
Robins are common birds in North America. Suppose that the wingspan of robins is approximately normal with mean 14 inches and standard deviation 0.7 inches.
-What is the 30th percentile of robin wingspans? Report your answer with two decimal places.
A) 13.63 inches
B) 13.21 inches
C) 12.74 inches
D) 12.36 inches

Question

Quizplus · Accepted Answer

The 30th percentile corresponds to a z-score of approximately -0.524. Using the formula for a normal distribution, X = μ + zσ, where μ = 14 and σ = 0.7, we calculate X = 14 + (-0.524)(0.7) ≈ 13.63 inches.

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