The correlation coefficient ranges from -1 to +1. A strong negative correlation implies a value close to -1, which is indeed much smaller than 0. While the source answer is technically incomplete regarding positive correlation, it is correct in the context of identifying a strong negative relationship.
1532
What is the property of the correlation coefficient with respect to the variables x and y?
The correlation coefficient is symmetrical with respect to the variables x and y, meaning that the correlation between x and y is identical to the correlation between y and x. This property arises because the formula for the Pearson correlation coefficient involves the product of the deviations of both variables from their respective means, which remains unchanged regardless of the order in which the variables are assigned.
1533
What is the defined range for the partial correlation coefficient?
Like the simple Pearson correlation coefficient, the partial correlation coefficient measures the strength and direction of a linear relationship between two variables while controlling for the effects of one or more additional variables. Consequently, its value is strictly bounded between -1 and +1, inclusive.
1534
Which of the following scenarios best illustrates an inverse relationship between two variables?
An inverse relationship occurs when one variable increases while the other decreases. In economics, the law of demand states that as the price of a product increases, the quantity demanded typically decreases, assuming other factors remain constant. This is a classic example of a negative or inverse correlation between price and demand.
1535
What is the primary purpose of calculating the correlation coefficient between two variables, x and y?
The correlation coefficient, typically denoted as r, quantifies the degree and direction of the linear association between two quantitative variables. It ranges from -1 to +1, where values closer to the extremes indicate a stronger linear relationship, while values near zero suggest little to no linear association. It does not predict specific values, which is the function of regression analysis.
1536
What is the typical range for the correlation coefficient (r) when there is a positive linear relationship between a dependent and an independent variable?
The Pearson correlation coefficient (r) ranges from -1 to +1. A value of +1 indicates a perfect positive linear relationship, while 0 indicates no linear relationship. When the dependent variable increases as the independent variable increases, the correlation is positive, falling within the range of (0, 1]. Option C represents a subset of this positive range, which is consistent with a positive relationship.
1537
In the context of correlation analysis, what is the nature of the variables involved?
In correlation analysis, both variables are typically treated as random variables. This means that both x and y are subject to natural variation and are not controlled by the researcher. This distinguishes correlation from simple linear regression, where the independent variable is often treated as fixed or controlled by the experimenter to observe the effect on the dependent variable.
1538
If the correlation coefficient between two variables x and y is positive, what happens to variable y when variable x decreases?
A positive correlation coefficient indicates that the two variables move in the same direction. Therefore, if variable x decreases, variable y must also decrease to maintain the positive relationship between the two variables.
1539
How is the correlation coefficient classified in terms of its measurement properties?
The correlation coefficient is considered a relative measure because it is a dimensionless index. It expresses the strength and direction of a linear relationship between two variables on a standardized scale ranging from -1 to +1. Because it is independent of the units of measurement of the original variables, it allows for the comparison of relationships across different datasets regardless of scale.
1540
Which of the following options does not represent a valid application or utility of correlation analysis?
Correlation analysis is a fundamental statistical tool used to quantify the strength and direction of relationships between variables. It is widely applied in research to test hypotheses and in business to support data-driven decision-making. Since all listed options are valid utilities, the question implies that none of them are 'not related'.