Playing Video Games A new study provides some evidence that playing action video games strengthens a person's ability to translate sensory information quickly into accurate decisions. Researchers had 23 male volunteers with an average age of 20 look at moving arrays on a computer screen and indicate the direction in which the dots were moving.1 Half of the volunteers (11 men) reported playing action video games at least five times a week for the previous year, while the other 12 reported no video game playing in the previous year. The response time and the accuracy score were both measured. A 95% confidence interval for the mean response time for game players minus the mean response time for non-players is -1.8 to -1.2 seconds, while a 95% confidence interval for mean accuracy score for game players minus mean accuracy score for non-players is -4.2 to +5.8.   a) Is it likely that game players and non-game players are basically the same in response time? If not, which group is faster (with a smaller response time)?     Likely to be basically the same   Not likely to be the same, and game players are faster   Not likely to be the same, and non-game players are faster   (b) Is it likely that game players and non-game players are basically the same in accuracy? If not, which group is more accurate?     Likely to be basically the same   Not likely to be the same, and game players are more accurate   Not likely to be the same, and non-game players are more accurate

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 + ...