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Socioeconomic status has no influence on bathing rates and eating patterns.
Socioeconomic status has no influence on bathing rates and eating patterns.
False
What are the three types of correlations discussed in the content?
What are the three types of correlations discussed in the content?
Cross-sectional correlations, lag cross-correlations, autocorrelations
The term used for when a variable at an earlier timepoint is associated with another variable at a later timepoint is called __________.
The term used for when a variable at an earlier timepoint is associated with another variable at a later timepoint is called __________.
lag cross-correlation
Match the following types of correlations with their descriptions:
Match the following types of correlations with their descriptions:
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Autocorrelations measure how one variable relates to itself over time.
Autocorrelations measure how one variable relates to itself over time.
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In the context of child language learning, what does 'temporal precedence' refer to?
In the context of child language learning, what does 'temporal precedence' refer to?
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What does a correlation coefficient (r) of +1.0 indicate?
What does a correlation coefficient (r) of +1.0 indicate?
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In a scatterplot, if points are widely spread out, it indicates a strong correlation.
In a scatterplot, if points are widely spread out, it indicates a strong correlation.
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Define a monotonic relationship in the context of correlation.
Define a monotonic relationship in the context of correlation.
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Spearman's correlation is used for examining the strength and direction of the ______ relationship between two variables.
Spearman's correlation is used for examining the strength and direction of the ______ relationship between two variables.
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Match the following correlation types with their appropriate usage:
Match the following correlation types with their appropriate usage:
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Which statement correctly describes the assumption of independence in a correlational study?
Which statement correctly describes the assumption of independence in a correlational study?
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The closer the data points are to the regression line, the weaker the correlation between the variables.
The closer the data points are to the regression line, the weaker the correlation between the variables.
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In the context of correlational strategies, what variable is usually represented on the x-axis of a scatterplot?
In the context of correlational strategies, what variable is usually represented on the x-axis of a scatterplot?
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A ______ indicates the strength and direction of the correlation between two variables and ranges from -1.0 to +1.0.
A ______ indicates the strength and direction of the correlation between two variables and ranges from -1.0 to +1.0.
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Which of the following is an example of a non-linear correlation?
Which of the following is an example of a non-linear correlation?
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What does a negative lag value indicate in the context of parent-infant interactions?
What does a negative lag value indicate in the context of parent-infant interactions?
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Positive autocorrelation means that a behavior is decreasing over time.
Positive autocorrelation means that a behavior is decreasing over time.
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What is autocorrelation?
What is autocorrelation?
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A positive correlation in depressive symptoms means that symptoms are _______ over time at specific intervals.
A positive correlation in depressive symptoms means that symptoms are _______ over time at specific intervals.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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In infant development, what does the 'Lag' refer to?
In infant development, what does the 'Lag' refer to?
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Circadian rhythms are associated with repeating patterns that occur over a 12-hour cycle.
Circadian rhythms are associated with repeating patterns that occur over a 12-hour cycle.
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What association is being tested when measuring lag cross-correlations?
What association is being tested when measuring lag cross-correlations?
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In the context of pediatric development, when a child's behavior precedes a parent's action, it implies that the child is exhibiting _______ behavior.
In the context of pediatric development, when a child's behavior precedes a parent's action, it implies that the child is exhibiting _______ behavior.
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Match the following examples with their respective correlation types:
Match the following examples with their respective correlation types:
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Which of the following would likely indicate a negative autocorrelation over time?
Which of the following would likely indicate a negative autocorrelation over time?
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When observing positive autocorrelation, behaviors remain stable with no change over time.
When observing positive autocorrelation, behaviors remain stable with no change over time.
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How often do depressive symptoms in bipolar disorder tend to repeat?
How often do depressive symptoms in bipolar disorder tend to repeat?
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The method used to observe if a behavior at one time point correlates with the same behavior at a different time point is known as _______.
The method used to observe if a behavior at one time point correlates with the same behavior at a different time point is known as _______.
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Study Notes
Correlational Research Strategy
- Correlational research aims to demonstrate a relationship between two variables, but does not establish cause-and-effect.
- Experimental research, in contrast, demonstrates a cause-and-effect relationship between two variables.
- Correlational strategy is used to study the relationship between two or more variables.
- Correlation describes the direction and degree of relationship between variables.
- Data collection is strictly correlational, meaning no variables are manipulated; variables are measured.
- Observation, surveys, and physiological measurements are common methods of data collection.
- Correlational research has high external validity, meaning it can be generalized to real-world settings, but it does not allow for conclusions about causality.
- A study examining the relationship between cheese consumption and deaths from bedsheet tangling has a high correlation but cannot imply causation.
- Examples of correlational studies include the relationship between chocolate price and quality (marketing), caffeine intake and alertness (basic research), and movie topics and music preferences (art design).
- Scatter plots are used to visualize the relationship between variables in correlational studies. Each point on a scatterplot represents one measurement.
- Each item or person is represented by only one data point on a scatter plot. Each point is assumed to be independent of others in the data set. In other words, no two points can come from the same individual.
Correlation Coefficient
- A correlation coefficient (r) quantifies the strength and direction of a linear relationship between two variables. The values range from -1.0 to +1.0. The sign denotes the direction of the correlation.
- For ordinal data, Spearman's rank order correlation (rs) is used.
- For ratio or interval data, Pearson correlation (r) is used.
- A correlation coefficient of 1.0 or -1.0 indicates a perfect linear relationship.
- Values near zero suggest a weak linear relationship.
Nonlinear Correlations
- A linear correlation shows a consistent change in one variable as the other variable changes.
- A nonlinear correlation shows inconsistent changes.
Spearman's Rank-Order Correlation
- Spearman's correlation quantifies the strength and direction of a monotonic relationship between two ordinal variables.
- Monotonic relationship means that the two variables move in the same direction (i.e., both increasing or decreasing).
When to Use Spearman's Rank-Order Correlation
- Spearman's rank-order correlation is used when the data is ordinal and not interval or ratio scale.
- Monotonic relationships must be identified for the data to be meaningful using Spearman's correlation coefficient.
Calculating a Spearman Correlation
- Raw data scores are used to compute a Spearman rank correlation.
- Data is ranked from lowest to highest.
- The difference between the ranks is calculated for each score pair.
Calculating a Pearson Correlation
- A correlation coefficient describes the relationship between two variables, quantifying the direction and strength of a linear relationship.
- Direction, form, and consistency are the three characteristics a correlation assesses.
- Interval or ratio scale data is common in behavioral research.
Direction of Correlation
- Positive correlation: Higher values of one variable tend to be associated with higher values of the other variable; lower values of one variable tend to be associated with lower values of the other.
- Negative correlation: Higher values of one variable tend to be associated with lower values of the other variable and vice versa.
- No, or zero, correlation: There is no observable, predictable relationship between variables.
Form of Correlation
- Linear relationship: Data points tend to cluster around a straight line.
- Positive linear relationship: One variable increases consistently with a predictable increase in the other variable at a similar rate.
- Nonlinear relationship: Data points do not cluster around a straight line; these often follow a curve.
- The Pearson correlation is used to assess linear correlations, while Spearman's rank correlation assesses monotonic relationships.
Strength of Correlation
- The strength of a correlation is determined by the absolute value of the correlation coefficient, which ranges from -1.0 to +1.0.
- A value close to 1 or -1 indicates a strong relationship. A value close to 0 indicates a weak relationship.
- The magnitude of a correlation coefficient is ordinal such that a value of .8 is not twice as strong as .4.
Correlation: Outliers
- Outliers are data points that deviate significantly from the general trend of the data set, which can strongly influence the correlation.
- Outliers are common in measures of variance, meaning that they can be 2-3 standard deviations from the mean value.
Correlations in Spearman & Pearson
- Spearman correlation is less sensitive to outliers than Pearson correlation.
- Re-assigning ranks addresses outlier issues in Spearman, which is advantageous.
Correlation: Significance and Interpretation of Value
- Statistical significance tests determine if a correlation is unlikely due to chance.
- A low p value suggests it is a real relationship that likely exists in the population.
- Small sample sizes increase the chance of observing high correlations even when there is no relationship in the population, and vice versa.
- A p-value less than 0.5 is often used as a criterion to denote a statistically significant correlation.
Correlation and Outcomes
- Cross-sectional correlations test if two variables measured simultaneously are related to one another.
- Lagged cross-correlations determine if one variable precedes another variable in time.
- Autocorrelations investigate whether the same variable measured at different points in time are related.
- Correlational methods do not establish causality, but they can provide valuable insight into relationships between variables.
Advantages of Correlational Methods
- Often quick and efficient.
- Sometimes the only method available due to practical or ethical constraints, such as the inability to manipulate a variable like personality traits or due to ethical considerations.
- Reflect natural events.
- Higher degree of external validity.
Limitations of Correlational Methods
- Does not indicate causation.
- Variable values are sensitive to outside variables, which may influence the data set.
- Directionality problem: Variables cannot reliably be identified as a cause and effect relationship.
- Third-variable problem: A third unknown variable is likely influencing the data relationship between variables.
Timepoint-Based Correlations
- Cross-sectional correlations: relationships between variables at a single time point.
- Lagged correlations: Relationships between an earlier variable and a later variable.
- Autocorrelations: Relationships between a variable measured at different points in time.
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Description
Explore the fundamentals of correlational research strategies. This quiz covers the key concepts, methods, and implications of correlational versus experimental research. Test your understanding of how relationships between variables are studied and the importance of not implying causation.