A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 450 seconds and a standard deviation of 50 seconds. Find the probability that a randomly selected boy in secondary school can run the mile in less than 335 seconds.

Is the answer 0.0107? Anyone please

4 answers

can some one please help me!!!
You are given the normal model N(450, 50)

Find the z score for 335 seconds.
z = (x-u)/s
where u = mu and s = sigma.

z = (335-450)/50
z = -2.3

Now use the normal cumulative distribution function on a calculator or program to find the P(z<-2.3)

normalCDF(-99,-2.3) = .0107
Marth this are my choices
A) 0.9893
B) 0.0107
C) 0.4893
D) 0.5107

So I'm assuming it's letter B? correct
Dahhhh lol