Question

Activity 22-8: UFO Sighters' Personalities In a 1993 study, researchers took a sample of people who claimed to have had an intense experience with an unidentified flying object (UFO) and a sample of peo- ple who did not claim to have had such an experience. They then compared the two groups on a wide variety of variables, including IQ. The sample mean IQ of the 25 people in the study who claimed to have had an intense experience with a UFO was 101.6; the standard deviation of these IOs was 8.9. As 100 is a common mean value for IQ scores, suppose that you want to test H: u = 100 vs. Ha:H# 100. (a Identify clearly what the symbol u represents in this context. (b) Is this a one-sided or a two-sided test? Explain how you can tell.

Answer 1

a) $\mu$ represents the IQs of the persons who have had an intense experience with an UFO.

b) The mentioned hypothesis in the question is a two-sided hypothesis because the given alternative hypothesis states that the mean is not equal to 100 which means there is a possibility of less than 100 or more than 100. Hence this is a two-sided test.

d) $\mu$ = 100

sample size n = 25

sample mean M = 101.6

sample std dev s = 8.9

test statistic t = = (101.6 - 100)/(8.9/5) = 0.899

M s/ - u (n)

considering alpha = 5%

P-Value=0.3776 test t=0.899 t=-2.604 t=2.604

g)

p-value = 0.378

This P value indicates that IQs of the persons who have had an intense experience with an UFO is 100, we would obtain a difference in 37.8% of studies due to random sampling error.

since p-value is greater than 0.05 we fail to reject null hypothesis, and cocnclude that there is no significant evidence that IQs of the persons who have had an intense experience with an UFO is different than 100.