9If the null hypothesis is true and we run the MannWhitney t

9.If the null hypothesis is true and we run the Mann–Whitney test on data, the expectation is that the _____ in the two groups will be approximately equal.

Means

Ranks

Variances

Mean ranks

9b.What might be a reason to choose parametric tests over non-parametric tests, even if some parametric assumptions are violated?

Non-parametric tests are harder to carry out.

Non-parametric tests are less powerful.

Parametric tests are less robust.

Parametric tests are more likely to show causal effects.

9c.A researcher conducts some research in which they identify a significant positive correlation between the number of children a person has and their life satisfaction (r = .42). Which of the following is it inappropriate to conclude from this research?

a.That having children makes people more satisfied with their life.

b.That someone who has children is likely to be happier than someone who doesn\'t.

c.That the consequences of having children are unclear.

d.That it is possible to predict someone\'s life happiness partly on the basis of the number of children they have.

9d.What is multicollinearity?

a.When predictor variables correlate very highly with each other.

b.When predictor variables have a linear relationship with the outcome variable.

c.When predictor variables are correlated with variables not in the regression model.

d.When predictor variables are independent.

9e .A researcher summarizes her results of research into the use of a specific type of inhaler for asthma sufferers as follows: ‘predictors significantly favored inhaler use (adjusted R²= .38; p = .015). Inhaler A was the strongest predictor of improved breathing ( = .39; p = .001) followed by inhaler B ( = .28; p = .0015)’. Which of the following would be the best interpretation of the variables in relation to these results?

a.39% of the variation in inhalers

b.28% of the variation in inhalers

c.38% of the variation in inhalers

d.None of the above

Solution

9..If the null hypothesis is true and we run the Mann–Whitney test on data, the expectation is that the RANKS in the two groups will be approximately equal.

9b.What might be a reason to choose parametric tests over non-parametric tests, even if some parametric assumptions are violated?

Non-parametric tests are harder to carry out.

9c.A researcher conducts some research in which they identify a significant positive correlation between the number of children a person has and their life satisfaction (r = .42). Which of the following is it inappropriate to conclude from this research?

b.That someone who has children is likely to be happier than someone who doesn\'t.

9d.What is multicollinearity?

a.When predictor variables correlate very highly with each other.