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Exam 3 Review. Definitions (1). Process of collecting sample data. Definitions(2). In a(n) ___________________, subjects are assigned randomly to each of the cells formed by the treatments. Randomization is an effort to control for all unmeasured factors. . Definitions(3).
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Definitions (1) • Process of collecting sample data
Definitions(2) • In a(n) ___________________, subjects are assigned randomly to each of the cells formed by the treatments. Randomization is an effort to control for all unmeasured factors.
Definitions(3) • Originally developed for use in survival analysis, where the response y is typically measures as 0 or 1, depending on whether the experimental unit “survives.”
Definitions(4) Individuals on which an experiment is conducted ___________________.
Definitions(5) • These data measure variables of interest, but do not attempt to influence the responses.
Explanations(1) What is the difference between a factor and a treatment?
Explanations(2) Describe a completely random design and when you would use it.
Explanations(3) • Describe a randomized block design and when it is advantageous to use it.
Explanations(4) • What do MST and MSE represent, and what conclusions can we draw if we have this information?
Explanations(5) • When is it appropriate to use a follow-up analysis of multiple comparisons?
Design(1) • Few people want to eat discolored french fries. Potatoes are kept refrigerated before being cut for French fries to prevent spoiling and preserve flavor. But immediate processing of cold potatoes causes discoloring due to complex chemical reactions. The potatoes must therefore be brought to room temperature before processing. In this experiment, tasters will rate the color and flavor of french fries prepared from several groups of potatoes. The potatoes will be fresh picked or stored for a month at room temperature or stored for a month refrigerated. They will then be sliced and cooked either immediately or after an hour at room temperature. • What are the factors and their levels?
Design(2) • Few people want to eat discolored french fries. Potatoes are kept refrigerated before being cut for French fries to prevent spoiling and preserve flavor. But immediate processing of cold potatoes causes discoloring due to complex chemical reactions. The potatoes must therefore be brought to room temperature before processing. In this experiment, tasters will rate the color and flavor of french fries prepared from several groups of potatoes. The potatoes will be fresh picked or stored for a month at room temperature or stored for a month refrigerated. They will then be sliced and cooked either immediately or after an hour at room temperature. • What are the treatments?
Design(3) • Few people want to eat discolored french fries. Potatoes are kept refrigerated before being cut for French fries to prevent spoiling and preserve flavor. But immediate processing of cold potatoes causes discoloring due to complex chemical reactions. The potatoes must therefore be brought to room temperature before processing. In this experiment, tasters will rate the color and flavor of french fries prepared from several groups of potatoes. The potatoes will be fresh picked or stored for a month at room temperature or stored for a month refrigerated. They will then be sliced and cooked either immediately or after an hour at room temperature. • What are the response variables?
Design(4) • Few people want to eat discolored french fries. Potatoes are kept refrigerated before being cut for French fries to prevent spoiling and preserve flavor. But immediate processing of cold potatoes causes discoloring due to complex chemical reactions. The potatoes must therefore be brought to room temperature before processing. In this experiment, tasters will rate the color and flavor of french fries prepared from several groups of potatoes. The potatoes will be fresh picked or stored for a month at room temperature or stored for a month refrigerated. They will then be sliced and cooked either immediately or after an hour at room temperature. • Describe the design of the experiment
Design(5) • Few people want to eat discolored french fries. Potatoes are kept refrigerated before being cut for French fries to prevent spoiling and preserve flavor. But immediate processing of cold potatoes causes discoloring due to complex chemical reactions. The potatoes must therefore be brought to room temperature before processing. In this experiment, tasters will rate the color and flavor of french fries prepared from several groups of potatoes. The potatoes will be fresh picked or stored for a month at room temperature or stored for a month refrigerated. They will then be sliced and cooked either immediately or after an hour at room temperature. • If you want each taster to rate fries from all treatments, how could you use randomization in presenting fries to the tasters?
Application(1) What are the assumptions for ANOVA?
Application(2) • How can we check the assumption of normality? Equal variances?
Application(3) • Do managers make inferences about an employee based on absenteeism? A sample of 33 managers were presented with a booklet describing the absenteeism of three hypothetical employees. One had “excellent” attendance, one had “average” attendance, and one was “absence-prone”. The managers estimated the total number of days each employee was absent during a 2-year period. The goal of the study was to compare the mean number of absences for the 3 employees. • What are the treatments and blocks for this experiment?
Application(4) • Do managers make inferences about an employee based on absenteeism? A sample of 33 managers were presented with a booklet describing the absenteeism of three hypothetical employees. One had “excellent” attendance, one had “average” attendance, and one was “absence-prone”. The managers estimated the total number of days each employee was absent during a 2-year period. The goal of the study was to compare the mean number of absences for the 3 employees. • Specify the null hypothesis to be tested. The ANOVA resulted in a test statistic of F=5.42 for treatments with p-value of .009. Interpret this result.
Application (5) • Do managers make inferences about an employee based on absenteeism? A sample of 33 managers were presented with a booklet describing the absenteeism of three hypothetical employees. One had “excellent” attendance, one had “average” attendance, and one was “absence-prone”. The managers estimated the total number of days each employee was absent during a 2-year period. The goal of the study was to compare the mean number of absences for the 3 employees. • What unwanted source of variability is the blocking intending to control? How can we determine if there is evidence that blocking by employers was effective in controlling it?
