Collecting Data: Homework Date: ______
1) State what method you would use to collect data to answer the following questions.
a) Has the percentage of students that drop out before grade 12 increased since 1975?
b) Does a program of regular physical exercise make workers more productive?
c) Who will be elected mayor in the next election?
d) Does eating an apple every day really keep the doctor away?
e) How many students in your school have part-time jobs?
f) Does mandatory seatbelt legislation reduce the number of traffic fatalities?
g) How many damaged eggs can be expected in a day’s production.
2) Lisa is conducting a survey of students to find out how much students earn from part-time jobs. Lisa doesn’t want to survey everyone, so she decides to ask a sample of 50 students. Suggest some methods Lisa could use to select an unbiased sample.
3) A scientist is studying the effects of a special diet on student grades. Why is a control group necessary?
4) Ten year, ago, city Council increased the speed limit on the road in front of Carolyn’s house. Carolyn wants to know if traffic accidents have also increased. She examines the records of accidents on the road for 10 years before and 120 years after the speed limit was changed, and concludes that accidents have increased 20% due to the speed limit change. Is this necessarily a valid conclusion? What other factors should Carolyn consider? What are some problems that can arise by drawing conclusions from past records?
5) Tory works on the school paper and wants to know how many students like the cafeteria food. Tory selects 2 students at random. One student enjoys the food and the other prefers to bring sandwiches made at home. Based on that survey, Tory writes an article “50% of Students dislike Cafeteria Food.” Comment on Tory’s conclusion.
6) A brand-name toothpaste advertises “2 out of 3 Dentists Recommend Dent-Paste to Their Patients.” What other information would you like to have before accepting the claim?
7) Look through newspapers and magazines to find two examples of each of the three techniques of collecting data.
8) An inspector of computer software inspected 80 diskettes at random and found that 3 were flawed. Find the relative frequency of damaged diskettes. If 45 000 diskette were produced, how many can the manufacturer expect to be returned as damaged? How could the inspector ensure that the selection of diskettes was random?
9) An unbiased telephone survey of 800 households showed that 56 used Sudsy Soap and 47 used Bubbles Soap. Estimate the number of boxes of Sudsy Soap and Bubbles Soap in Toronto’s population of 3.5 million people?
10) Last year a game warden captured and tagged 50 deer. This year, the warden captures 140 deer and discovers that 8 are tagged. Calculate the estimated deer population of the park.
11) By surveying your class, predict the number of Canadians that part their hair on the right side of their head. Why is your survey biased?
12) An inspector at a garment industry passed 57 of the 65 shirts that were inspected for flaws. How many shirts can the company expect to be flawless in a shipment of 1250 shirts?