In: Statistics and Probability
Professor Brown is interested to see if the graduating seniors in her sociology class have higher or lower college GPAs compared to their respective high school GPAs.
Subtracting the high school GPA from the college GPA and to the nearest hundredth, what is the mean of differences?
A social epidemiologist is interested to see if young adults drink more alcohol if they’re in college compared to those not in college. He selects a sample of 1000 young adults (ages 18-23) in Burlington, VT. Five hundred respondents were attending one of three colleges in the area (sample 1), and 500 were not, and had never been, in college (sample 2). He asked the respondents how many alcohol drinks they consumed on a typical Friday evening. The mean number of drinks for sample 1 (college students) is 3.6, and the mean for sample 2 (non-students) is 1.8.
Click on the epidemiologists’ research hypothesis for this test.
A human factors psychologist wants to know if a new computer-generated voice is either easier or harder to comprehend than human speech. To test this, he gathers 30 volunteers and assigns each to one of two groups. Both groups hear a selection being read. One group's selection is read in the computer-generated voice, the other is read by a human. The results of the experiment, the number of words from the selection that were transcribed correctly, are presented below. Is there a difference in comprehensibility?
Computer Voice Group n = 15 mean = 227 variance = 841
Human Voice Group n = 15 mean = 261 variance = 1764
What is the decision for the hypothesis test conducted in 11.31 with alpha = .05.
A
Reject the nulll hypothesis
B
Fail to reject the null hypothesis