Suggested Answer
Given mean = 26.7 mpgstandard deviation =7.2 mpg Finda) what percent of compact cars( for this brand) have a fuel economy greater than 26.7 mpgb) What is the z-score( or standard score) for fuel economy of 25 mpgc) find the probability that a random selected new compact ( from this brand) has a fuel economy less than 25 mpg. Explanationa) mean = 26.7 mpgstandard deviation =7.2 mpg P(X > 26.7) = [tex]\begin{gathered} P\left(X>26.7\right)=P(\frac{X-\mu}{\sigma}>\frac{26.7-26.7}{7.2}) \\ \\ =P(Z>0) \\ =0.5 \end{gathered}[/tex]b) [tex]\begin{gathered} z=\frac{X-\mu}{\sigma} \\ =\frac{25-26.7}{7.5} \\ =-0.22667 \\ =-0.23 \end{gathered}[/tex]c)[tex]\begin{gathered} P(Z<-0.23)=P(Z>0.23) \\ =1-P(Z\leq0.23) \\ =1-0.590954 \\ =0.409046 \\ =0.40905 \end{gathered}[/tex]Final Answera)b)c)0.40905