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    Methods of Computation for Significance

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    A personnel psychologist studying adjustment to the job of new employees
    found that employees' amount of education (in number of years) predicts ratings
    by job supervisors two months later. The regression constant in the linear
    prediction rule for predicting job ratings from education is 0.5 and the regression
    coefficient is .40. (a) Indicate the predictor variable, and (b) the criterion
    variable. (c) Write the linear prediction rule for this example. Indicate the predicted
    job rating for employees with each of the following amount of education
    (in years): (d) 8, (e) 10, (f) 17, (g) 19, and (h) 21.

    A clinical psychologist has found that scores on a new depression scale predict
    satisfaction with psychotherapy. The regression constant in the linear prediction
    rule for predicting satisfaction from the depression score is 12 and the regression
    coefficient is .4. (a) Indicate the predictor variable, and (b) the
    criterion variable. (c) Write the linear prediction rule for this example. Indicate
    the predicted satisfaction for people with each of the following depression
    scores: (d) 8, (e) 6, (f) 5, (g) 3, and (h) 0.

    Evolutionary theories often emphasize that humans have adapted to their physical
    environment. One such theory hypothesizes that people should spontaneously
    follow a 24-hour cycle of sleeping and waking-even if they are not
    exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers
    were placed (individually) in a room in which there was no light from the
    outside and no clocks or other indications of time. They could turn the lights on
    and off as they wished. After a month in the room, each individual tended to
    develop a steady cycle. Their cycles at the end of the study were as follows: 25,
    27, 25, 23, 24, 25, 26, and 25.

    Using the 5% level of significance, what should we conclude about the theory
    that 24 hours is the natural cycle? (That is, does the average cycle length under
    these conditions differ significantly from 24 hours?) (a) Use the steps of hypothesis
    testing. (b) Sketch the distributions involved. (c) Explain your answer
    to someone who has never taken a course in statistics.

    Do students at various colleges differ in how sociable they are? Twenty-five
    students were randomly selected from each of three colleges in a particular region
    and were asked to report on the amount of time they spent socializing each
    day with other students. The results for College X was a mean of 5 hours and
    an estimated population variance of 2 hours; for College Y, M = 4, S2 = 1.5;
    and for College Z, M = 6, S2 = 2.5. What should you conclude? Use the .05
    level. (a) Use the steps of hypothesis testing, (b) figure the effect size for the
    study; and (c) explain your answers to (a) and (b) to someone who has never
    had a course in statistics.

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    https://brainmass.com/statistics/hypothesis-testing/methods-of-computation-227866

    Solution Summary

    This solution shows step-by-step calculations to identify types of variables, linear prediction rule, predicted job rating for each scenario. A full statistical analysis is also conducted with a decision rule.

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