8) Assume that adults have IQ scores that are normally distributed with a mean o

Question

8) Assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard 8) deviation of 15 (as on the Wechsler test). Find P15, which is the IQ score separating the bottom 15% from the top 85%. A) 83.3 C) 84.0 D) 82.5 Solve the problem. Round to the nearest tenth unless indicated otherwise. 9) Assume that women have heights that are normally distributed with a mean of 63.6 inches and a9) standard deviation of 2.5 inches. Find the value of the quartile Q3. A) 65.3 inches B) 67.8 inches C) 64.3 inches D) 66.1 inches

Explanation / Answer

solution:-.
8) option B) 84.5
given that mean = 100 , standard deviation = 15
the z-value that has a left tail of 15% is -1.0364
formula
=> x = z*s + µ
=> x = -1.0364 * 15 + 100
=> x = 84.5

9) option A) 65.3 inches
given mean = 63.3 , standard deviation = 2.5
the value of the quartile Q3 is 0.75
the z value for tail is 0.674
formula
=> x = z*s + µ
=> x = 2.5*(0.674)+63.6
=> x = 65.285
=> x = 65.3 inches (rounded)

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