n a study examining the effect of alcohol on reaction time, Liguori and Robinson (2001) found that evenmoderate alcohol consumption significantly slowed response time to an emergency situation in a drivingsimulation. In a similar study, researchers measured reaction time 30 minutes after participants consumed one6-ounce glass of wine. Again, they used a standardized driving simulation task for which the regular populationaverages μ = 400 msec. The distribution of reaction times is approximately normal with σ = 40. Assume that theresearcher obtained a sample mean of M = 422 for the n = 25 participants in the study.a. Are the data sufficient to conclude that the alcohol has a significant effect on reaction time? Use a two-tailed testwith α = .01.

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 + ...