Welcome to AP Statistics - Home



Name: _________________________________ Date: ____________________ Period: __________Practice: Experimental Design Day 1Agricultural experts are trying to develop a bird deterrent to reduce costly damage to crops in the United States. An experiment is to be conducted using garlic oil to study its effectiveness as a nontoxic, environmentally safe bird repellant. The experiment will use European starlings, a bird species that causes considerable damage annually to the corn crop in the United States. Food granules made from corn are to be infused with garlic oil in each of five concentrations of garlic —0 percent, 2 percent, 10 percent, 25 percent, and 50 percent. The researchers will determine the adverse reaction of the birds to the repellant by measuring the number of food granules consumed during a two-hour period following overnight food deprivation. There are forty birds available for the experiment, and the researchers will use eight birds for each concentration of garlic. Each bird will be kept in a separate cage and provided with the same number of food granules. (a) For the experiment, identifythe treatments: The treatments are the different concentrations of garlic in the food granules. Specifically, there are five treatments: 0 percent, 2 percent, 10 percent, 25 percent and 50 percent.the experimental units: The experimental units are the birds (starlings), each placed in an individual cage.the response that will be measured: The response is the number of food granules consumed by the bird.(b) After performing the experiment, the researchers recorded the data shown in the table below.58102510413900202565027961400Construct a graph of the data that could be used to investigate the appropriateness of a linear regression model for analyzing the results of the experiment. 10287007874000Based on your graph, do you think a linear regression model is appropriate? Explain. The curved pattern in this scatterplot reveals that a linear regression model would not be appropriate for modeling the relationship between these variables.Multiple Choice PrepIn a study of Parkinson’s disease, 100 volunteers had incisions made through their skulls. The patients were randomly sorted into two groups, one of which had a new drug inserted into the brain. In the other group, the skulls were closed with no treatment given. The patients did not know who received the drug. In the weeks to follow all 100 volunteers showed similar improvement in physical condition. What is this an example of?The effect of a treatment unit(B) The placebo effect (C) The control group effect(D) Sampling Error(E) Voluntary response bias50 migraine patients are randomly selected from hospital records. Half of the patients are told to drink ice water and sit in the dark when they next experience a migraine; the remaining patients are told to use neither of these possible remedies. Participants then report back as to relief, if any. Faults of this experimental design include all of the following except:Lack of randomization (There is no indication that randomization is being used to decide which patients have the treatment of ice water and darkness and which are in the control)Confounding variables (There is no way to tell whether it was the ice water or darkness that helped)Lack of blindingUnclear factor levels (We won’t know how much water or length of time in the dark)Measurement of response variable (How do they plan on measuring “relief”)Which of the following is most useful in establishing cause-and-effect relationships?A complete censusA least-squares regression line showing high correlationA simple random sample (SRS)A well-designed, well-conducted survey incorporating chance to ensure a representative sampleA controlled experimentWhich of the following is most important in minimizing the placebo effect?Replication and randomization Replication and blindingRandomization and blindingRandomization and a controlBlinding and control (Use of a control group and blinding as to which subjects are in the control group are the best tools to minimize the possibility of confounding due to the placebo effect. Replication and randomization are important parts of a good design, but they do not impact the placebo effect as does the use of control and blinding.)A bank wishes to survey its consumers. The decisions is made to randomly pick ten customers who just have checking accounts, ten customers who just have savings accounts, and then ten customers who have both checking and savings accounts. This procedure is an example of which type of sampling?Cluster(B)Convenience(C) Simple random(D) Stratified(E) Systematic ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download