A researcher predicts that showing a certain film will change people's attitudes toward alcohol.  The researchers then randomly select 36 people, show them the film, and give them an attitude questionnaire. The mean score on the attitude questionnaire for this sample of people is 70.  In the general population, the average score for people on this test is 75, with a standard deviation of 12 (assume the alpha level = .05) 1. Conduct the hypothesis test using a two-tailed test with alpha = .05 2. What is your conclusion regarding the null hypothesis?  Should you reject o fail to reject the null hypothesis? 3. What can you conclude about the film and attitudes toward alcohol based on your hypothesis test results.

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 + ...