Question

The Bespan of a laptop battery is normally distributed. If the meanifespan of a batteryis 4 years with a standard deviation of 1.6 years what is the probability that the nextlaptop battery you purchase will last between 3.5 and 5.5 years!15.21%84.79%55.19%44.81%

Answer 1

Formula

$\begin{gathered} Z=\text{ }\frac{x-\mu}{\sigma} \\ \text{Where} \\ Z=standardscore \\ x=observedvalue \\ \mu=meanofthesample \\ \sigma=standarddeviationofthesample \\ Z=\text{ }\frac{3.5-4}{1.6} \\ Z=-0.3125 \\ \\ \\ Z=\text{ }\frac{5.5-4}{1.6} \\ Z=0.9375 \end{gathered}$

Z=standard score

x=observed value

u=mean of the sample

standard deviation of the sample