The second GRE training course (B) is moderately expensive ($275 per course). The average score on the GRE quantitative section for graduates of this course is 625. Recall, the average score for people with no training who took the GRE quantitative section is 555 with a standard deviation of 139. We will draw several samples of 25 people from the population of students who participated in Training Course B. You will need a copy of this page before you go choose "go to applet."
For each sample that you draw, you should record the following information; Sample Mean and Z-score given that the population mean is 555. Space is provided below.
For this example, choose from pulldown box Alternate Mean = 625, enter in the box marked N = 25. Now click set.
Click on Draw a sample, and record the value shown for mean in the first space below, also record the z-score for each value. Then click on Draw a sample nineteen more times and record each mean and z.
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How many of these 20 sample means would you consider to be "surprising" given the hypothesized population mean was 555. Consider any result that would occur less than 5% of the time to be surprising.
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