Question

the length of adult parakeets is normally distributed. if the mean length is 8 inches with a standard deviation of 0.25 inches, what is the probability that a randomly selected adult parakeet will be less than 7.55 inches long? 15.43% 96.41% 5.74% 3.59%

Explanation:

Step1: Calculate z - score

$z=\frac{x-\mu}{\sigma}$, where $x = 7.55$, $\mu=8$, $\sigma = 0.25$. So $z=\frac{7.55 - 8}{0.25}=\frac{- 0.45}{0.25}=-1.8$.

Step2: Find probability from z - table

Looking up $z=-1.8$ in the standard normal distribution table, the corresponding probability is $0.0359$ or $3.59\%$.

Answer:

3.59%