5.8 Fuel efficiency of Prius: Fueleconomy.gov, the official US government source for fuel economy information, allows u
Posted: Sun Jul 10, 2022 10:09 am
5.8 Fuel efficiency ofPrius: Fueleconomy.gov, the official USgovernment source for fuel economy information, allows users toshare gas mileage information on their vehicles. The histogrambelow shows the distribution of gas mileage in miles per gallon(MPG) from 14 users who drive a 2012 Toyota Prius. The sample meanis 53.3 MPG and the standard deviation is 5.2 MPG. Note that thesedata are user estimates and since the source data cannot beverified, the accuracy of these estimates are not guaranteed.
(a) The EPA claims that a 2012 Prius gets 50 MPG (city and highwaymileage combined). Do these data provide strong evidence againstthis estimate for drivers who participate on fueleconomy.gov?The hypotheses for the test are:
To execute this hypothesis test we should use a:
because:
There are degrees of freedom for this test.The test statistic is: (please round to two decimalplaces)The p-value for this hypothesis test is: (pleaseround to four decimal places)The conclusion for the hypothesis test is:
(c) Calculate a 95% confidence interval for the average gas mileageof a 2012 Prius by drivers who participate onfueleconomy.gov.We are % confident that the true population gas mileageof a 2012 Prius by drivers who participate on fueleconomy.gov isbetween mpg and mpg. (please roundto one decimal place)
(a) The EPA claims that a 2012 Prius gets 50 MPG (city and highwaymileage combined). Do these data provide strong evidence againstthis estimate for drivers who participate on fueleconomy.gov?The hypotheses for the test are:
To execute this hypothesis test we should use a:
because:
There are degrees of freedom for this test.The test statistic is: (please round to two decimalplaces)The p-value for this hypothesis test is: (pleaseround to four decimal places)The conclusion for the hypothesis test is:
(c) Calculate a 95% confidence interval for the average gas mileageof a 2012 Prius by drivers who participate onfueleconomy.gov.We are % confident that the true population gas mileageof a 2012 Prius by drivers who participate on fueleconomy.gov isbetween mpg and mpg. (please roundto one decimal place)