Question

I just need help on questions 7 and 8

The U.S. Department of Energy's Fuel Economy Guide provides fuel efficiency data for cars and trucks. (See exercise 35 on page 77 in your textbook for a similar problem.) Use the data in the FuelData sheet in this workbook to generate excel output to answer the following questions. Please note that units are "liters" for engine size and "miles per gallon" for highway fuel efficiency. Put the output in given space on FuelData sheet. Each orange numerical answer cell below MUST reference generated Excel output cells in the FuelData sheet. Question 5A What is range for engine size? 2.3297 What is the variance for highway fuel efficiency? Question 5B 0.3199 What is IQR for engine size? 0.9985 Question 5C Question 6 What is the shape of the highway fuel efficiency distribution? Why? NOTE 1: Skewed right must select>, skewed left must select Mean Standard Error 0.959531644 Standard Error 0.0676026 34.5 Median Median 2.496138 Mode Mode 2.4406682 39 0.5656037 Standard Deviation Standard Deviation 8.028017708 Sample Variance Sample Variance Kurtosis -0.695838 Kurtosis -1.155393662 -0.190239233 Skewness Skewness 0.0121586 Range Range Minimum 1.442213 Minimum 19 3.7719418 Maximum Maximum 47 Sum Sum Count- Count Count 70 Count-> 70 Q1 Q1 Q1-> 1.9969 Q1-> 26.0000 Q3 2.9954 Q3 39.0000

Answer 1

Question 7:

For X = 0.7993:

$\mu$ = 2.4961

$\sigma$ = 0.5656

k

0.7993 2.4961 -3 0.5656

For X = 4.1929:

4.1929 2.4961 = +3 0,5656

By Chbyshev's Rule, at least 88.89% of the data lie within 3 Standard Deviations of the mean.

Thus, we write the answer as follows:

Chebyshev's rule predicts that 88.89 precent of engine data should be between 0.7993 and 4,1929 liters, which are $\pm$3 standard deviations away from the mean.

Question 8:

Standard Deviation of Engine Size = 0.5656

Mean of Engine Size = 2.4961

So,

Coefficient of Variation of Engine Size = (0.5656/2.4961) X 100 = 22.66 %

Standard Deviation of Highway Fuel Efficiency = 8.0280

Mean of Highway Fuel Efficiency = 33.0143

So,

Coefficient of Variation of Highway Fuel Efficiency = (8.0280/33.0143) X 100 = 24.32 %

Since Coefficient of Variation of Highway Fuel Efficiency = 24.32 % is greater than Coefficient of Variation of Engine Size = 22.66 %, we conclude:

Highway Fuel Efficiency varied most.