Question

Past records show that the times, in seconds, take to run 100m by children at a school can be modelled by a normal distribution witha mean of 16.12 and a standard deviation of 1.60.

(a) find that the probability that a child runs 100m in less than 15s.

(b) certs awarded to fastest 30% of race.
estimate to 2dp the slowest time taken to run the 100m race

Answer 1

any???

Answer 2

X~N(16.12, 1.60^2)

Answer 3

lalaly to the rescue ^_^

Answer 4

Let x be the random variable that represents the time in seconds
P(X<15)=\[P(Z<\frac{15-16.12}{1.6})\]then find it from the table

Answer 5

how about b?

Answer 6

b was the one i wanted, but i thought it would need a too

Answer 7

i need (b)

Answer 8

answer to (a) is 0.242

Answer 9

1-theta(0.7)