A corporation with a fleet of vihicles wanted to test the co

A corporation with a fleet of vihicles wanted to test the cost-effectiveness of using Motor Silk oil addictive. For the study, 6100 delivery and passeger vhhicles were tested for the same 3-month period in 2007 and then again in 2008. In 2007, the fleet was driven without motor silk. Then in 2008, Motor Silk was used according to the standard instructions. The average fuel economy increased from 18.97mpg to 21.72mpg. a) What kind of a study is this? b)Will they do one-tailed or two-tailed test? c)Explain in this context what a Type one error would be? d)Explain in this context what a type two error would be? e) Which type of error would the addictive manufacture consider more serious? f) If the vehicles with the addictive are indeed statistically significantly better, can the company conclude it is an effect of the addictive? Can they generate this result and recommend the addictive for all cars?

Solution

a)

T test

b)

two tailed test because we want to know if there is a difference

c)

reject Ho when Ho is true, that means reject that the average of fuel economy not are the same when actually are the same

d)

accept Ho when its false, that means accept that the average of fuel economy not are the same when acutally are not the same