Fill in the blanks by standardizing the normally distributed variable.
-The amount of time that customers wait in line during peak hours at one bank is normally distributed with a mean of 13 minutes and a standard deviation of 3 minutes. The percentage of Time that the waiting time lies between 11 and 13 minutes is equal to the area under the standard
Normal curve between ___ and ___.
A)-2, 0
B)0.62, 0.77
C)0, 0.67
D)-0.67, 0

Question

Fill in the blanks by standardizing the normally distributed variable.
-The amount of time that customers wait in line during peak hours at one bank is normally distributed with a mean of 13 minutes and a standard deviation of 3 minutes. The percentage of Time that the waiting time lies between 11 and 13 minutes is equal to the area under the standard
Normal curve between ___ and ___. 
A)-2, 0
B)0.62, 0.77
C)0, 0.67
D)-0.67, 0

Quizplus · Accepted Answer

To standardize a normally distributed variable, we use the formula $Z = \frac{X - \mu}{\sigma}$, where $X$ is the value, $\mu$ is the mean, and $\sigma$ is the standard deviation. For $X = 11$, $Z = \frac{11 - 13}{3} = -\frac{2}{3} = -0.67$. For $X = 13$, $Z = \frac{13 - 13}{3} = 0$. Therefore, the area under the standard normal curve we're looking for is between $-0.67$ and $0$.

Fill in the Blanks by Standardizing the Normally Distributed Variable