Determine and Interpret z-Scores
-A television station claims that the amount of advertising per hour of broadcast time has an average of 17 minutes and a standard deviation equal to 2.2 minutes. You watch the station for 1 hour, at a randomly selected time, and carefully observe that the amount of advertising time is equal to 7 minutes. Calculate the z-score for this amount of advertising time.
A) $z = - 4.55$
B) $z = 4.55$
C) $z = - 0.28$
D) $ z = 0.28$

Question

Determine and Interpret z-Scores
-A television station claims that the amount of advertising per hour of broadcast time has an average of 17 minutes and a standard deviation equal to 2.2 minutes. You watch the station for 1 hour, at a randomly selected time, and carefully observe that the amount of advertising time is equal to 7 minutes. Calculate the z-score for this amount of advertising time. 
A) $z = - 4.55$
B) $z = 4.55$
C) $z = - 0.28$
D) $ z = 0.28$

Quizplus · Accepted Answer

The z-score is calculated using the formula $z = \frac{(X - \mu)}{\sigma}$, where $X$ is the observed value, $\mu$ is the mean, and $\sigma$ is the standard deviation. Substituting the given values, $z = \frac{(7 - 17)}{2.2} = -4.55$.

Determine and Interpret Z-Scores -A Television Station Claims That the Amount

Determine and Interpret Z-Scores
-A Television Station Claims That the Amount