The average price for a gallon of gasoline in the United States is $3.73 and in Russia it is $3.40 (Bloomberg Businessweek, March 5-March 11, 2012). Assume these averages are the population means in the two countries and that the probability distributions are normally distributed with a standard deviation of $.25 in the United States and a standard deviation of $.20 in Russia. What percentage of the gas stations in Russia charge less than $3.50 per gallon?

Question

The average price for a gallon of gasoline in the United States is $3.73 and in Russia it is $3.40 (Bloomberg Businessweek, March 5-March 11, 2012). Assume these averages are the population means in the two countries and that the probability distributions are normally distributed with a standard deviation of $.25 in the United States and a standard deviation of $.20 in Russia.  What percentage of the gas stations in Russia charge less than $3.50 per gallon?

Mary Darby · Accepted Answer

Step 1 Given information: The mean price for a gallon of gasoline in the United States, μ1−=―$3.73 The mean price for a gallon of gasoline in the Russia, μ2−=―$3.40 Population standard deviation in the United States, σ1=$0.25 Population standard deviation in the Russia, σ2=$0.20 Step 2 We have to find the percentage of the gas stations in Russia charge less than $3.50 per gallon. Now, z-score for Russia is: z=x―−μσ z=3.50−3.400.20=0.5 So, probability of P(z&amp;lt;0.5) is: P(z&amp;lt;0.5)=0.6915 (From excel using formula =NORM.S.DIST(0.5,TRUE)) Therefore, the percentage of gas stations in Russia charge less than $3.50 per gallon is 69.15%.

The average price for a gallon of gasoline in the United States is $3.

Answered question

Answer & Explanation

New Questions in High school statistics