1. Ten years ago a study at a large midwestern university found that 18% of the students at the university were very optimistic about their prospects of finding a satisfying job after graduation. To determine if opinions have changed, an SRS of 100 students currently enrolled at the university was selected. 25% of those selected were optimistic about their prospects of finding a satisfying job after graduation. Let p be the proportion of the current student population that is optimistic about their prospects of finding a satisfying job after graduation. The P-value of a test of H0: p = 0.18, Ha: p 0.18 is
A. less than 0.05.
B. between 0.05 and 0.10.
C. greater than 0.10.
2. The 200 students in a statistics class were randomly divided into two groups of 100 students. Both groups were given the same midterm exam at the same time. One group took the exam in a classroom in which the air temperature was normal (68°). The other group was given the exam in a similar room in which the air temperature was unusually warm (84°). Both groups had one hour to complete the exam. Seventy-four of those taking the exam in the normal room passed, while only 66 of those taking the exam in the warm room passed. Let p1and p2 represent the probability of passing under normal and warm conditions, respectively. To determine if this is evidence that students perform worse under uncomfortable conditions, you test H0: p1 = p2, Ha: p1 > p2. The P-value of this test is
A. 0.1093.
B. 0.0547.
C. Both choices are correct.
3. We want to see if a panel of 30 expert wine testers can distinguish between a 1990 and 1991 Chardonnay. We present them each with three glasses of wine. The three glasses are either two glasses of the 1990 and one glass of the 1991 in a random order, or two glasses of the 1991 and one glass of the 1990 in a random order. The experts are supposed to identify which of the three glasses contains a different wine. If each of the 30 experts is just guessing and X is the number that guess correctly, then the sample proportion = X /30 who guess correctly has
