Question

commercials is a average of 16 minutes and a standard deviation equals 2.1 minutes. After watching the chanel for a hour randomly you observe the amount of commercials equals to 19 minutes Find the z score for the amount of commercials, round 2 decimals

Answer 1

To answer this question we will use the following formula to compute the z-score:

$\begin{gathered} z=\frac{x-\mu}{\sigma}, \\ \text{where x is the observed value, }\mu\text{ is the mean, and }\sigma\text{ is the standard deviation.} \end{gathered}$

Substituting x=19min, μ=16min, and σ=2.1min we get:

$z=\frac{19\min -16\min }{2.1\min }\text{.}$

Simplifying the above result we get:

$z=\frac{3}{2.1}=\frac{10}{7}\approx1.43.$

Answer: 1.43.