Exam 3: Displaying and Describing Categorical Data

Of the following, which is not a critical part of designing a good experiment?

Listed below are the names of the 20 pharmacists on the hospital staff. Use the random numbers listed below to select three of them to be in the sample. Clearly explain your method. 04905 83852 29350 91397 19994 65142 05087 11232 Pastore Back Spiridinov Ahl Hedge MacDowell Schissel Novelli Lavine Kaplan Highland Roundy Grubb Markowitz Glass Davies Golkowski Reeves Janis Yen

Explain why the last plan suggested above, selecting the ten trees closest to the parking lot, might be biased. Be sure to name the kind(s) of bias you describe and link it to the variable of interest.

Telephone poll The City Council decides to conduct a telephone poll. Pollsters ask a carefully chosen random sample of adults this question: "Do you favor the construction of a new prison to deal with the high level of violent crime in our State?" In what way might the proportion of "Yes" answers fail to accurately reflect true public opinion? Explain briefly. What kind of bias is this?

Max wants to start a farm to grow mussels. He needs to determine the best environment for growing them. He is going to try two different amounts of salt in the water (salinity) and three different water temperatures. For his experiment he has 18 aquariums, each with 20 mussels. He wants to see which environment produces the largest mussels. -Identify the response variable.

In an experiment the primary purpose of blocking is to

A Columbia University study linked soda consumption to behavior problems in children. Researchers examined data from a previous study that followed 2929 mother-child pairs. One survey asked about behaviors of the child and also about soda consumption. They found that the More soda the kids drank, the more behavior problems they had. What aspect of a well-designed experiment is absent from this study?

M&Ms The Mars candy company starts a marketing campaign that puts a plastic game piece in each bag of M&Ms. 25% of the pieces show the letter "M", 10% show the symbol "&", and the rest just say "Try again". When you collect a set of three symbols "M", "&", and "M" you can turn them in for a free bag of candy. About how many bags will a consumer have to buy to get a free one? Use a simulation to find out. a. Explain how you will use the random numbers listed below to conduct your simulation. b. Carefully label your simulation for 2 trials. Trial \# The run Outcome 1 69074 91976 33584 94138 87637 2 48324 77928 31249 64710 02295 c. State your conclusion.

Design an experiment to determine whether the diet and exercise programs are effective in helping dogs to lose weight.

Can watching a movie temporarily raise your pulse rate? Researchers have 50 volunteers check their pulse rates. Then they watch an action film, after which they check their pulse rates once more. Which aspect of experimentation is present in this research?

Max wants to start a farm to grow mussels. He needs to determine the best environment for growing them. He is going to try two different amounts of salt in the water (salinity) and three different water temperatures. For his experiment he has 18 aquariums, each with 20 mussels. He wants to see which environment produces the largest mussels. -Describe an advantage to random assignment of treatment.

Cloning A polling organization is investigating public opinion about cloning. They phone a random sample of 1200 adults, asking each person one of these questions (randomly chosen): A: "Do you favor allowing doctors to use cloned cells in attempts to find cures for such terrible diseases as Alzheimer's, diabetes, and Parkinson's?" B: "Should research scientists be allowed to use cloned human embryos in their experiments?" Which question do you expect will elicit greater support for cloning? Explain. What kind of bias is this?

Researchers plan to investigate a new medication that may reduce blood pressure for individuals with higher than average blood pressure. 90 volunteers with higher than average blood pressure are solicited. Volunteers are randomly assign 100 mg of the medicine, 200 mg of the medicine, or a placebo. Blood pressure will be measured at the beginning and at the conclusion of the study. -Identify the response variable.

Max wants to start a farm to grow mussels. He needs to determine the best environment for growing them. He is going to try two different amounts of salt in the water (salinity) and three different water temperatures. For his experiment he has 18 aquariums, each with 20 mussels. He wants to see which environment produces the largest mussels. -Explain how replication would be used in this study.

Which is true about sampling? I. An attempt to take a census will always result in less bias than sampling. II. Sampling error is usually reduced when the sample size is larger. III. Sampling error is the result of random variations and is always present.

A large manufacturer of batteries knows that, historically, 10% of its batteries come off the production line defective, and the remaining 90% of batteries come off the production line in working condition. Conduct a simulation to estimate how many batteries the company needs to pull off the production line in order to be sure of ending up with 10 working batteries. -Describe how you will use a random number table to conduct this simulation.

If we wish to compare the average PSAT scores of boys and girls taking AP* Statistics at this high school, which would be the best way to gather these data?

Public opinion A member of the City Council has proposed a resolution opposing construction of a new state prison there. The council members decide they want to assess public opinion before they vote on this resolution. Below are some of the methods that are proposed to sample local residents to determine the level of public support for the resolution. Match each with one of the listed sampling techniques. 1 cluster 2 convenience 3 judgment 4 multistage 5 simple (SRS) 6 stratified 7 systematic 8 voluntary response _ a) Place an announcement in the newspaper asking people to call their council representatives to register their opinions. Council members will tally the calls they receive. _ b) Have each council member survey 50 friends, neighbors, or co-workers. c) Have the Board of Elections assign each voter a number, then select 400 of them using a random number table. d) Go to a downtown street corner, a grocery store, and a shopping mall; interview 100 typical shoppers at each location. _ e) Randomly pick 50 voters from each election district. _ f) Call every 500th person in the phone book. _ g) Randomly pick several city blocks, then randomly pick 10 residents from each block. _h) Randomly select several city blocks; interview all the adults living on each block.

Researchers plan to investigate a new medication that may reduce blood pressure for individuals with higher than average blood pressure. 90 volunteers with higher than average blood pressure are solicited. Volunteers are randomly assign 100 mg of the medicine, 200 mg of the medicine, or a placebo. Blood pressure will be measured at the beginning and at the conclusion of the study. -Describe a disadvantage of using volunteers in this study.

Administrators at a hospital are concerned about the possibility of drug abuse by people who work there. They decide to check on the extent of the problem by having a random sample of the employees undergo a drug test. Several plans for choosing the sample are proposed. Name the sampling strategy in each. a. There are four employee classifications: doctors, medical staff (nurses, technicians, etc.) office staff, and support staff (custodians, maintenance, etc.). Randomly select ten people from each category. b. Each employee has a 4-digit ID number. Randomly choose 40 numbers. c. At the start of each shift, choose every tenth person who arrives for work. d. Randomly select a department (say, radiology) and test all the people who work in that department - doctors, nurses, technicians, clerks, custodians, etc.