Homework6: Problem 9 Previous Problem List Next (1 point) Scores on a certain in
ID: 3044741 • Letter: H
Question
Homework6: Problem 9 Previous Problem List Next (1 point) Scores on a certain intelligence test for children between ages 13 and 15 years are approximately normally distributed with = 1 17 and 21 (a) What proportion of children aged 13 to 15 years old have scores on this test above 99? Answer: (b) Enter the score which marks the lowest 30 percent of the distribution. Answer (c) Enter the score which marks the highest 10 percent of the distribution. Answer Note: You can earn partial credit on this problem.Explanation / Answer
a) P(X > 99)
= P(z > (99 - 117)/21)
= P(z > -0.86)
= 0.8043
b) z score corresponding to lowest 30% = -0.52
Hence,
Score = 117 - 0.52*21 = 106.08
c) z score corresponding to highest 10% = 1.28
Hence,
Score = 117 + 1.28*21 = 143.88
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.