Warm Up Define the null and alternate hypotheses for the following scenarios: 1) The DMV reports that 80% of all new drivers pass the road test on their first try. A local school’s newspaper randomly surveyed 90 students and found only 61 passed. Is this evidence the school’s pass rate is lower? 2) An “all you can eat” buffet restaurant investigated the impact of plate size on how much food customers ate. Customers randomly assigned a large plate consumed a mean of 740 calories while customers assigned a small plate consumed a mean of 670 calories. Is this evidence customers eat less with the smaller plates?

Review - #1 A 2007 study describes an experiment on a group of college students who all took the same class from the same instructor. Students were required to report to an assigned room to fill out a course evaluation. Typically only 45% of this instructor’s students gave her a favorable rating. However a random group of 80 students were given a candy bar before filling out the evaluation. Of these students 43 of them gave her a favorable rating. Is this statistically significant data that the candy bar induced the students to give a better evaluation?

Review - #2 A 2004 study investigated whether humans can swim faster in “syrup” than water. Data on 9 randomly selected swimmers was taken on swimming velocity (m/s) both in water and in water thickened with food grade guar gum. Is this statistically significant data that swimmers can swim faster in “syrup” than water? Swimmer 1 2 3 4 5 6 7 8 9 Water 0.90 1.00 1.20 1.25 1.35 1.50 1.70 1.80 1.85 Syrup 0.92 0.95 1.22 1.26 1.34 1.52 1.70 1.76 1.89