Blatchley Chapter 13 Quiz

. What is the maximum possible value for a correlation coefficient?

1.00

100

Infinity

.50

. How are positive and negative correlations also characterized?

Positive correlations are also called direct, and negative correlations are also called indirect.

Positive correlations are generally causal and negative correlations are relations.

Positive correlations and negative correlations are also called direct relations.

Positive correlations are between .5 and 1.0, and negative correlations are between -.5 and -1.0

. How are correlations best characterized?

In a positive correlations, when one variable changes, the other changes in the same direction. In a negative correlation, when one variable changes, the other decreases.

In positive correlations, when one variable increases, the other also increases. In a negative correlation, when one variable decreases, the other also decreases.

In a positive correlation, when one variable decreases, the other also decreases. In a negative correlation, when one variable increases, the other decreases.

None of the above are correct

.

Generally speaking, what kind of correlation would you expect between a children's age and their vocabulary?

positive

negative

no correlation

either negative or no correlation

. Which of the following is the strongest correlation?

.12

-.24

.39

-.61

. Which of the following is true regarding positive versus negative correlations?

Positive correlations occur when two variables change in the same direction. Negative correlations occur when two variables change decrease in the same direction.

Positive and negative correlations are both bounded between 1.00 and -1.00.

Positive and negative correlations increase in strength as they reach 0.00

Positive correlations are stronger than negative correlations.

. Which of the following indicates the weakest correlation?

.77

-.93

.01

-.38

. The null hypothesis for testing a correlation between two variable states which of the following?

The two variables of interest are correlated

The two variables of interest are not correlated

The two variables of interest have a causal relationship

The two variables of interest have a correlation coefficient greater than 0

.

Does water consumption relate to cognitive sharpness? A researcher records the amount of water individual in his sample drinks a day and measures their cognitive abilities using a test with scores that range from 0 (lowest) to 50 (highest). Use this data to answer the next four questions.

Water consumption (cups)	Test Score
12	44
14	39
18	48
19	41
12	29
11	37
13	33
16	50
17	43

How many degrees of freedom are in this test?

5

6

9

7

. When calculating a Pearson correlation for this data set, you are assuming that the relationship between two variables, if any, is...

positive

negative

linear

quadratic

. What is the critical value for the correlation? Assume Î± = .05.

.666

.632

.735

.576

. If the test is significant, what does it imply?

There is a linear relationship between water consumption and cognitive performance

There is a positive relationship between water consumption and cognitive performance

There is no relationship between water consumption and cognitive performance

There is evidence of a causal relationship between water consumption and cognitive performance

. The least squares regression line minimizes which of the following?

The variability in the data

The correlation coefficient

The coefficient of determination

The residuals

. In a regression analysis, if the b is positive, then that means...

the correlation is significant

the correlation is positive

the coefficient of determination is negative

the regression analysis is significant

. What does the a in a regression equation refer to?

It is the value when the independent variable is at 0

It is the value of the regression coefficient

It is the proportion of variance of the dependent variable that is explained by the independent variable

None of the above

. Which of the following is not a true limitation of the Pearson correlation?

It should only be used for relationships in which one assumes a linear relationship.

It can only be used for 3 variables.

It can only be used when the relationship is positive.

All of the above are correct.

. What does it mean if your dataset you collected for correlational research has truncated range?

One variable has a small range than the other

The sample's range is greater than that of the population

The sample's range a restricted portion of the population's variability

The sample's mean and median are much higher than the population's mean and median

. What is the likely outcome of having truncated range when calculating a correlation coefficient?

The sample correlation coefficient will be an overestimate of the population value.

The sample's correlation coefficient will be an underestimate of the population value.

The correlation coefficient will be more reliable than if truncated range were not present.

The correlation coefficient will still be a valid estimate of the population correlation.

. A researcher found the correlation between smoking and physical fitness score is r = -.4. What is the coefficient of determination?

-.16

-.2

.08

.16

. Which of the following is the correct formula for the coefficient of determination in a sample?

r²

r/2

2r

r

. Which of the following is true regarding the coefficient of determination?

smaller values are more likely to be statistically significant

the coefficient of determination is indirectly correlated with the correlation coefficient

Smaller coefficients of determination are associated with a stronger correlation

Larger coefficients of determinations are associated with stronger correlations

. The coefficient of determination and strength of the correlation coefficient for the same data set are...

positively correlated

negatively correlated

not correlated

sometimes positively correlated, sometimes negatively correlated

. Which of the following best describes causality in statistics?

If the data are correlational, causality is impossible.

If the data are analyzed by ANOVA, the results are always causal.

Correlational data can be causal.

Correlational data can be causal only if you analyze it correctly.

. Which of the following is false of possible hidden variables in correlations?

They can play a causal role.

They are generally not controlled for in the analysis.

Their effects can be eliminated even after the data is collected.

All of the above are true.

. Which of the following best describes the relationship between statistics and causality?

The method and the statistic are equally important in determining whether causality can be inferred from the results.

It's primarily the method that is important and not the statistic itself that allows for causal inferences.

The statistic is the most important piece of information that determines whether causality can be inferred; the method if irrelevant.

Causality has to do with neither the method nor the statistic, but rather it is generated from the research question.

Blatchley Chapter 13 Quiz

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