A psychologist wanted to study the effect of illicit drug use on one’s ability to focus or concentrate. The psychologist measured 40 participants’ ability to focus before and after taking a controlled amount of an illicit drug. In the results section, the psychologist writes: "There was a significant decline in focus/concentration from a mean of 18.41 (SD = 2.48) to 11.44 (SD = 2.69), t (39) = 10.87, p < .01 (one-tailed)."
Correlation
Correlation defines a relationship between two independent variables. It tells the degree to which variables move in relation to each other. When two sets of data are related to each other, there is a correlation between them.
Linear Correlation
A correlation is used to determine the relationships between numerical and categorical variables. In other words, it is an indicator of how things are connected to one another. The correlation analysis is the study of how variables are related.
Regression Analysis
Regression analysis is a statistical method in which it estimates the relationship between a dependent variable and one or more independent variable. In simple terms dependent variable is called as outcome variable and independent variable is called as predictors. Regression analysis is one of the methods to find the trends in data. The independent variable used in Regression analysis is named Predictor variable. It offers data of an associated dependent variable regarding a particular outcome.
- A psychologist wanted to study the effect of illicit drug use on one’s ability to focus or concentrate. The psychologist measured 40 participants’ ability to focus before and after taking a controlled amount of an illicit drug. In the results section, the psychologist writes: "There was a significant decline in focus/concentration from a mean of 18.41 (SD = 2.48) to 11.44 (SD = 2.69), t (39) = 10.87, p < .01 (one-tailed)."
a. What kind of t-test was used by the psychologist? Why?
b. Elaborate on each facet of the t-test results as you explain the impact of illicit drugs in this experiment.
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