Is this a directional (one-tailed) or nondirectional (two-tailed) hypothesis test?
Belinda Buttons of the Peerless Zipper Company is in charge of quality control for the production of their 12-inch zippers. Recently, she has become worried about a disturbing drop in the quality of the zippers produced by her division. The zippers should be normally distributed with ? = 12 and ? = .10. She randomly samples 100 zippers and finds their mean length to be 12.06 inches. Do Belinda's zippers differ significantly from the population of zippers?
Ans: Nondirectional hypothesis test because Belinda is looking only for deviations from the normal zipper length, regardless of the direction of that deviation.
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Research indicates that mastery learning approaches are superior to traditional instruction in several ways. Which one of the following conclusions should not be drawn on the basis of research on mastery learning?
a. Academic achievement is higher in classrooms that emphasize mastery learning. b. High-ability students are the primary beneficiaries of mastery learning approaches. c. Students remember material for a longer period of time when taught with a mastery learning approach rather than with traditional instructional methods. d. Some forms of mastery learning (e.g., Keller's PSI) promote regular study habits rather than procrastination and cramming.
LuAnn, a child development researcher, recently conducted a study in a hospital nursery to examine the feeding habits of newborn babies. She did not tell parents her identity or the purpose of her work when she asked them questions. This concern with LuAnn's study is most directly related to a concern with
a. external validity. b. internal validity. c. reliability. d. ethics.
Which type of instruction places sole responsibility for teaching and evaluating with the teacher?
a. direct instruction b. precision teaching c. open education d. computer assisted instruction
Although test scores are important in advising people about career choice, what other factors must also be considered?
a. IQ and educational attainment b. personality, values, and desires c. history of employment d. parents’ education and occupation