Answer:
The z score of the 65-mph speed limit is -0.75
Step-by-step explanation:
The z score is given by the relation;
[tex]z = \frac{x- \mu}{\sigma}[/tex]
Where:
Z = Normal (Standard) or z score
x = Observed speed score
μ = Mean, expected speed
σ = Standard deviation
Where we plug in the values for x = 65-mph, σ = 8 mph and μ = 71 mph, into the z-score equation, we get;
[tex]z = \frac{65-71}{8}= \frac{-6}{8} = -\frac{3}{4}[/tex]
Hence the z score of the 65-mph speed limit =-3/4 or -0.75.