Exploring Two–Variable Data
In a study examining the relationship between hours studied (X) and exam scores (Y), what significance does finding a correlation coefficient close to -1 imply about these variables?
The exam scores tend to stay constant regardless of how many hours are studied since they are perfectly uncorrelated.
The number of hours studied causes lower exam scores with near certainty due to causation implied by high correlation.
There exists no significant relationship between hours studied and exam scores because correlations near -1 indicate lack of association.
There exists a strong negative linear relationship between hours studied and exam scores.
If a study finds that there is a correlation of between the number of hours studied and exam scores, which of the following best explains why we cannot conclude causation from this correlation?
There might be an outlier influencing the high correlation coefficient observed.
The value of may change if more data points are added, altering the conclusion.
The presence of confounding variables may affect both the hours studied and exam scores.
The sample size for the study could be too small to establish a strong correlation.
What does a correlation coefficient of 0 indicate about two variables?
No linear relationship.
A perfect negative linear relationship.
The data points all fall perfectly on a line.
A perfect positive linear relationship.
In a scatterplot, data points lie perfectly on a downward-sloping straight line; what value would you expect for the sample correlation coefficient?
-1
Exactly zero
Greater than zero
One
Given that variable X has a strong positive association with Y for lower values but a weak or no association for higher values, how might this heteroscedasticity impact the calculation and interpretation of their Pearson's r?
It may lead to an underestimate of r for low values and overestimate at high values.
Heteroscedasticity does not affect Pearson's r calculations or interpretations.
It will cause an underestimation in r only at higher value ranges.
It will result in a consistently overestimated r across all ranges.
What type of graph is typically used to visually assess the strength and direction of a correlation between two quantitative variables?
Histogram
Bar graph
Scatterplot
Pie chart
In a scatter plot, if the points are widely scattered and do not follow a clear pattern, the correlation coefficient is likely to be?
Close to 1
Close to 0
Close to -1
Impossible to determine

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When researchers find that their calculated r-value is close to -1, which conclusion regarding variable X affecting variable Y is supported by this statistic?
Variable X causes decreases in variable Y due to an inverse causation effect indicated by r-value alone.
Variable X has no apparent effect on variable Y since r-values only measure linear relationships.
Variable X has an inconsistent effect on variable Y since negative values signify unreliable results in correlations.
Variable X has a strong negative linear association with variable Y.
What value does the correlation coefficient have when two variables are perfectly unrelated?
One (1)
Less than zero (- values)
Zero (0)
Cannot be calculated
The term "r^2" in statistics refers to which of the following concepts?
The variance of Y given X.
The coefficient of determination.
The slope of least squares regression line.