The America Automobile Association reported that the mean price of a gallon of regular grade gasoline in the United States in October 2020 was $2.82. An economist is interested in determining whether the mean price of regular grade gasoline is cheaper (less than) in New York State.  To test this, the economist sample 50 gas stations in NY and find the mean price of regular grade gasoline to be $2.77. Assume the standard deviation for the price of regular grade gasoline is $0.15. Use the critical value method to perform a hypothesis test at the 0.05 level of significance.   a) what is the conclusion for this test?

Definition Definition Measure of central tendency that is the average of a given data set. The mean value is evaluated as the quotient of the sum of all observations by the sample size. The mean, in contrast to a median, is affected by extreme values. Very large or very small values can distract the mean from the center of the data. Arithmetic mean: The most common type of mean is the arithmetic mean. It is evaluated using the formula: μ = 1 N ∑ i = 1 N x i Other types of means are the geometric mean, logarithmic mean, and harmonic mean. Geometric mean: The nth root of the product of n observations from a data set is defined as the geometric mean of the set: G = x 1 x 2 ... x n n Logarithmic mean: The difference of the natural logarithms of the two numbers, divided by the difference between the numbers is the logarithmic mean of the two numbers. The logarithmic mean is used particularly in heat transfer and mass transfer. ln x 2 − ln x 1 x 2 − x 1 Harmonic mean: The inverse of the arithmetic mean of the inverses of all the numbers in a data set is the harmonic mean of the data. 1 1 x 1 + 1 x 2 + ...