Question

Autistic children are often evaluated and given a developmental score from 1 to 5, where 1 represents the absence of signs (normal development), and 5 represents the maximal severity of signs (severe retardation). One proposed distribution for the developmental scores of autistic children is as follows: P(x) 0.29 0.11 0.01 0.58 0.01 1.00 Developmental Score (X) 2 4 Total Assuming that this probability distribution is correct, answer the following questions (2 decimal accuracy) The probability that an autistic child has a developmental score of 3 is Number The probability that an autistic child has a developmental score of at least 3 is Number

Answer 1

CLEARLY FROM THE TABLE IT CAN BE SEEN THAT

the probability for Developmental score 3 is 0.01

SO THE PROBABILITY THAT AN AUTISTIC CHILD HAS A DEVELOPMENTAL SCORE 3 IS 0.01

PART B)

NOW WE WANT P(SCORE AT LEAST 3)

MEANS P(SCORE 3 OR 4 OR 5)

i.e add the probability of 3, 4, 5 to get 0.01 + 0.58 + 0.01 to get 0.60

SO THE PROBABILITY THAT AN AUTISTIC CHILD HAS A DEVELOPMENTAL SCORE OF AT LEAST 3 IS 0.60