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vs. Eric Kannengieszer and Colin Buckley. Gas Prices. Our objective was to run a series of tests involving gas prices Exxon vs. Lukoil Pennsylvania vs. New Jersey Exxon PA vs. Exxon NJ Lukoil PA vs. Lukoil NJ Wanted to determine what station was cheapest. Background.
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vs. Eric Kannengieszer and Colin Buckley Gas Prices
Our objective was to run a series of tests involving gas prices • Exxon vs. Lukoil • Pennsylvania vs. New Jersey • Exxon PA vs. Exxon NJ • Lukoil PA vs. Lukoil NJ • Wanted to determine what station was cheapest Background
We Google Maps searched PA and NJ Exxon and Lukoil stations and randomly selected 10 of each. • We numbered each location and used our calculator to randomly select the stations • We picked four days from our break and called each location to record the prices What we did
Exxon vs. lukoil • Ho: µE=µL • Ha: µE≠µL • Conditions: 1. 2 Independent SRS 1. yes, performed 2 SRS 2. pop1≥10n 2. more than 800 Lukoil’s/Exxon’s pop2≥10n 3. 2 normal populations 3. histograms shows normal populations Conditions met →Use students t distribution →2 sample t-test
Exxon vs. Lukoil • We reject the Ho because the p-value is smaller than alpha.05. • We have sufficient that the average price of Exxon gas is not equal to the average price of Lukoil gas.
New jersey vs. Pennsylvania • Ho: µNJ=µPA • Ha: µNJ<µPA • Conditions: 1. 2 Independent SRS 1. yes, performed 2 SRS 2. pop1≥10n 2. more than 800 Lukoil’s/Exxon’s pop2≥10n 3. 2 normal populations 3. histograms shows normal populations VS. Conditions met →Use students t distribution →2 sample t-test
new jersey vs. Pennsylvania • We reject the Ho because the p-value is smaller than alpha .05. • We have sufficient that the mean price of New Jersey is less than the mean price of Pennsylvania.
Exxon nj vs. exxon pa • Ho: µNJ=µPA • Ha: µNJ<µPA • Conditions: 1. 2 Independent SRS 1. yes, performed 2 SRS 2. pop1≥10n 2. more than 400 Exxon’s pop2≥10n 3. 2 normal populations 3. histograms shows normal populations Conditions met →Use students t distribution →2 sample t-test
Exxon NJ vs. Exxon PA • We reject the Ho because the p-value is smaller than alpha .05. • We have sufficient evidence that the mean price of Exxon’s in NJ is less than that of Exxon’s in PA.
Lukoil nj vs. Lukoil pa • Ho: µNJ=µPA • Ha: µNJ<µPA • Conditions: 1. 2 Independent SRS 1. yes, performed 2 SRS 2. pop1≥10n 2. more than 400 Lukoil’s pop2≥10n 3. 2 normal populations 3. histograms shows normal populations Conditions met →Use students t distribution →2 sample t-test
Lukoil NJ vs. Lukoil PA • We reject the Ho because the p-value is smaller than alpha .05. • We have sufficient evidence that the mean price of Lukoil’s in NJ is less than that of Lukoil’s in PA.
Bias and error • Miscommunication over the phone • Individual stores within the chain have the same price
conclusions • New Jersey gas is substantially cheaper than Pennsylvania gas • Exxon has a wider range of price, but Lukoil has a lower mean price overall • NJ Lukoil’s is the cheapest • If you want gas, go to New Jersey and find a Lukoil