Question

The times of all 15 year olds who run a certain race are approximately normally distributed with a given mean mc026-1.jpg = 18 sec and standard deviation mc026-2.jpg = 1.2 sec. What percentage of the runners have times less than 14.4 sec?
0.15%
0.30%
0.60%
2.50%

Answer 1

Answer:

A.  0.15%

Step-by-step explanation:

The times of all 15 year old who run a certain race are approximately normally distributed with a given mean as 18 sec and standard deviation as 1.2 sec.

We know that,

$z=\dfrac{X-\mu}{\sigma}$

where,

X = raw score = 14.4

μ = mean = 18

σ = standard deviation = 1.2

Putting the values,

$z=\dfrac{14.4-18}{1.2}=\dfrac{-3.6}{1.2}=-3$

Finding the the probability from z score table, we get

$P(z$

Answer 2

0.15% the answer is A