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Engineers are testing company fleet vehicle fuel economy (miles per gallon) perf

ID: 3207669 • Letter: E

Question

Engineers are testing company fleet vehicle fuel economy (miles per gallon) performance by using different types of fuel. One vehicle of each size is tested. Does this sample provide sufficient evidence to conclude that there is a significant difference in treatment means?

                87 Octane           89 Octane           91 Octane           Ethanol 5%          Ethanol 10%

Compact            27.9                      30.6                      19.7                      29.2                      29.4       

Mid-Size            17.3                      18.1                      17.8                      19.7                     31.7       

Full-Size             28.8                      28.7                      18.3                      28.7                      30.8       

SUV     17.8                      22.6                      18.1                      17.2                      28.9       

PictureClick here for the Excel Data File

(a)          Choose the correct statement.

               

               

                Fuel type is the blocking factor and vehicle size is the treatment.

                Fuel type is the treatment and vehicle size is the blocking factor.

(b)          Fill in the boxes. (Round your SS values to 3 decimal places, F values to 2 decimal places, and other answers to 4 decimal places.)

    

                                                           Two-Factor ANOVA

Source SS                                          df         MS         F              p-value

Treatments (Vehicle Size)                         

Blocks (Fuel Type)        

Error                                  

Total   

           Group                        Mean             n                     Std. Dev

    87 Octane      

    89 Octane      

    91 Octane      

    Ethanol 5%    

    Ethanol 10%                  

    Compact               

    Mid-Size    

    Full-Size

    SUV

    Total   

Explanation / Answer

Perform the Two-Way ANOVA without replication in excel for the given data and you would get the following output -

-------------------------------------------------------

(a)

As we are testing the efficiency of the fuel type for different sizes, so fuel here is the blocking factor and size is the treatment.

So, Fuel type is the blocking factor and vehicle size is the treatment.

-------------------------------------------------------------------------------

b)

The tables can be filled using the ANOVA output obtained from excel as -

And, the second one as -

Note that from the excel output we have got the variance but we need the standard deviation to complete the second table. So, take the square root of the variances to get the standard deviation as shown above.

Anova: Two-Factor Without Replication SUMMARY Count Sum Average Variance Compact 5 136.8 27.36 19.253 Mid-Size 5 105.6 21.12 42.712 Full-Size 5 135.3 27.06 24.783 SUV 5 104.6 20.92 24.507 87 Octane 4 91.8 22.95 39.05667 89 Octane 4 100 25 32.80667 91 Octane 4 73.9 18.475 0.709167 Ethanol 5% 4 94.8 23.7 37.83333 Ethanol 10% 4 121.8 30.45 2.896667 ANOVA Source of Variation SS df MS F P-value F crit Rows 191.9055 3 63.9685 5.186565 0.015808 3.490295 Columns 297.018 4 74.2545 6.020554 0.006772 3.259167 Error 148.002 12 12.3335 Total 636.9255 19