independent variables. DIF: Cognitive Level: Application REF: Page 573 3.Why does a researcher decide to calculate odds ratio instead of calculating linear regression when comparing whether aperson voted in the last election and the person’s gender? a. Voting records are sealed. b . Both predictor and dependent variable are dichotomous. c. Odds ratio is a simpler calculation. d . Strength of relationship is not an issue. ANS: B When both the predictor and the dependent variable are dichotomous (having only two values; also called binary), the odds ratio is a commonly used statistic to obtain an indication of association. Linear regression is used to determine relationships with interval or ratio data. The odds ratio ( OR ) is defined as the ratio of the odds of an event occurring in one group to the odds of it occurring in another group. Put simply, the OR is a way of comparing whether the odds of a certain event is the same for two groups. DIF: Cognitive Level: Analysis REF: Page 575 MULTIPLE RESPONSE 1. A researcher collects a nationally based set of data about cholesterol levels and age at first circulatory incident (myocardial infarction or cerebrovascular accident). The researcher performs a linear regression analysis in order to do which of the following? (Select all that apply.) a. Estimate the age at which circulatory incidents are likely to occur, given the cholesterol level. b . Determine how well the data fit the theoretical framework. c. Calculate the strength of the relationship between cholesterol levels and circulatory incidents. d . Determine whether there is a linear relationship between cholesterol levels and circulatory incidents. e. Derive the formula for the line of best fit. f. Obtain information from which to construct a better scatter plot. ANS: A, C, D, E Simple linear regression provides a means to estimate the value of a dependent variable based on the value of an independent variable. Through regression, the strength of the relationship between two variables can be determined. Simple linear regression is an effort to explain the dynamics within the scatter plot by developing a formula for a straight line that best fits the data. This has nothing to do with a theoretical framework. A scatter plot precedes development of a regression formula. DIF: Cognitive Level: Application REF: Page 570
2. A researcher is studying number of cats in the home, and number of rodents plus crawling insects in the home, daily carbohydrate intake and the next day’s first morning Accu-Chek value. After drawing a scatter plot, the researcher develops a multiple regression equation and determines R as .75 and R 2 as .5625. What does the calculated value R 2 represent? (Select all that apply.) a. It means the standard error, squared. b . It is the amount of rodent plus insect count that can be explained by the number of cats.
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- Fall '16
- Denise Cauble
- Nursing, Qualitative Research, researcher, Cognitive Level