Question

6)  You have a group of 500 students.  On a particular test, μ = 72 and σ = 10.

      a)  How many students scored above 88?

      b)  What is the number of students scoring below 60?

7)  100 9-year old boys take turns throwing a baseball as far as they can.  For the group,

      average distance thrown is 80 feet and σ = 20 feet.      

      a) What percentage threw 100 feet or more?

      b) How many threw 45 feet or less?

      c) What distance would be the top 10%?

      d) What is the probability that a child picked at random threw between 59-99 feet?

      e) What distances are so extreme that only 1% did it?

      f) What distances are so extreme that only 5% did it?

Answer 1

(there are more than 1 questions, as per policy i am answering first question, but I'll answer all its parts)

6.

n>=30 so we can assume normal distribution

a.

number of students scoring above 88 = 0.0548*500 = 55 (rounded to nearest integer)

number of students scoring above 88 = 55

b.

number of students scoring below 60 = 0.1151*500 = 115 (rounded to nearest integer)

number of students scoring below 60 = 115

(please UPVOTE)

P(z<Z) table :