Respuesta :
Question
The times of all 15 year old who run a certain race are approximately normally distributed with a given mean Mu = 18 sec and standard deviation Sigma = 1. 2 sec. What percentage of the runners have times less than 14. 4 sec?.
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,
where,
X = raw score = 14.4
μ = mean = 18
σ = standard deviation = 1.2
Putting the values,
Finding the the probability from z score table, we get
