MATH200 — Practice Quiz: Chapter 12 — 21 min

Practice Quiz: Chapter 12

Work this like a regular quiz, using only your crib sheet. Give yourself a maximum of 21 minutes, then turn to the solutions and see how you did.

Show that requirements are met. Round test statistics to two decimal places and probabilities to four decimal places.

Remember, you must show your work for full credit on any problems involving computation.

1(points: 7) You think that people’s ice cream favorites are 25% each vanilla and chocolate, 20% strawberry, 15% butter pecan, 8% rocky road, and 7% other or no preference. You randomly survey 1000 people and find preferences are 220 vanilla, 255 chocolate. 190 strawberry, 170 butter pecan, 95 rocky road, and 70 other or no preference. Using α=0.05, was your idea right or wrong?

favor oppose unsure total 440 400 120 960 320 480 100 900 760 880 220 1860

2(points: 7) Democrats and Republicans were surveyed for their opinions on gun control, and the results are shown in the table at right. Based on this sample, does a person’s opinion on gun control depend on party affiliation, at the .05 level of significance?

3(points: 1) 425 school children were surveyed about what they want to be when they grow up, out of a choice of five professions. The results were Teacher 80, Doctor 105, Lawyer 70, Police officer 70, Firefighter 100.

Obviously these particular children preferred some occupations over others. You want to test whether their preferences reflect a real difference in the population. What model do you use? (Write only the model; don’t do a hypothesis test.)

Solutions to this practice quiz are available at http://www.tc3.edu/instruct/sbrown/stat/