1. The Scholastic Assessment Test (SAT) is standardized to be normally distribut

Question

1. The Scholastic Assessment Test (SAT) is standardized to be normally distributed with a mean of 500 and a standard deviation of 100. Find the precentage of scores in between a score of 300 and a score of 700. (Round to two decimal places, no leading zero) 2. For a of score with a mean of 111 and a standard deviation of 8, what is the percentile rank of 90? (Round to two decimal places, no leading zero.) The answer is not 121.3 3. The average price for a new car is $18,000 and the stadard deviation is $1500, The z-score of a car that costs $19,000, is ? (round to two decimal places, no leading zeros) The answer is not -.66

Explanation / Answer

u have asked 3 questions , i am giving u solution of 1st

1) mean = 500

standard deviation = 100

distribution is normal

therefore formula to be used

z = (x-mean)/standard deviation

p(300<x<700) =

For x = 300 , z = (300 - 500) /100 = -2 and for

x = 700, z = (700 - 500) / 100 = 2

Hence P(300 < x < 700) = P(-2 < z < 2) = [area to the left of z = 2] - [area to the left of -2]

= 0.9772 - 0.0228 = 0.9544

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