Answer:
[tex]\frac{15,7 - 20}{1,26} = - 3,4[/tex]
Step-by-step explanation:
To determine the Z - score, it is calculated as follows:
[tex]\frac{X - X_{avg} }{σ}[/tex]
Then:
[tex]\frac{15,7 - 20}{1,26} = - 3,4[/tex]
It means that there are more than 3 standar deviations below the advertised mileage.