Maria's family drove 140 mi to her grandparents' house and averaged 56 mi/h on the way there. On the return trip, they avera
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Answer:
15.39%
Step-by-step explanation:
Step 1
Find the z-value associated to the given datum x, in this case x = 28 mpg
<em>z is given by the formula </em>
where is the mean of the distribution and
is the standard deviation. In this case,
Step 2
Locate the z-value in the table of z-values of the normal distribution.
(See table attached) and read the number corresponding to this z-value. In this case is highlighted in the table and its value is 0.34614.
<em>This numbers gives us the % of vehicles with a mpg between 0 and 28. </em>
Step 3
As we know that the total area under the curve for z > 0 is 0.5, then we have to subtract 0.34614 from 0.5 to obtain the % of cars with a mpg greater than 28 mpg.
0.5 - 0.34614 = 0.15386
so, the % of 2016 vehicles that have better gas mileage than the Beetle's gas mileage is 15.39 % (rounded to two decimals)
