the amount of daily time that teenagers spend on a brand a cell phone is normally distributed with a given…
the amount of daily time that teenagers spend on a brand a cell phone is normally distributed with a given mean $mu = 2.5$ hr and standard deviation $sigma = 0.6$ hr. what percentage of the teenagers spend more than 3.1 hr?\no 5%\no 10%\no 16%\no 32%
Answer
Explanation:
Step1: Calculate the z - score
The z - score formula is $z=\frac{x-\mu}{\sigma}$, where $x = 3.1$, $\mu=2.5$ and $\sigma = 0.6$. $z=\frac{3.1 - 2.5}{0.6}=\frac{0.6}{0.6}=1$
Step2: Find the proportion of data to the left of the z - score
Using the standard normal distribution table, the proportion of data to the left of $z = 1$ is approximately $0.8413$.
Step3: Find the proportion of data to the right of the z - score
The proportion of data to the right of $z$ is $1 - 0.8413=0.1587\approx 16%$.
Answer:
16%