PY 211 Chapter 15 True/False

The formula for the Spearman correlation coefficient was derived from the formula for the Pearson correlation coefficient

True

The formula for the phi correlation coefficient was derived from the formula for the Pearson correlation coefficient

True

The formula for the point-biserial correlation coefficient was derived from the formula for the Pearson correlation coefficient

True

The sign (+ or -) of a correlation coefficient indicates the direction of a relationship between two factors

True

The value of the sum of products can be positive or negative

True

Three assumptions for a correlation are homoscedasticity, linearity and normality

True

To summarize correlations, we report strength, direction & the p-value for each correlation coefficient

True

The closer that data points fall to the regression line, the more closely two factors are related

True

The coefficient of determination is mathematically equivalent to eta-squared

True

The correlation coefficient can be converted to a chi square statistic

True

Linearity is the assumption that the best way to describe a pattern of data is using a straight line

True

Outliers can change both the direction & strength of a correlation

True

A correlation of r=.50 in a sample of 15 participants is statistically significant for a two-tailed test at a .05 level of significance

False

A positive correlation is always stronger than a negative correlation

False

If r=0.026 and df=10, then t=7.20

False

Restriction of range occurs when an unanticipated variable not accounted for in a research study that could be causing or associated with observed changes in one or more measured variables

False

The assumption of normality requires that the range of scores observed in a sample is the same of the possible range of scores in the population

False

The coefficient of determination is a measure of significance

False

The coefficient of determination is the square root of the correlation coefficient

False

The denominator of the pearson correlation measures the extent to which two factors vary together

False

The point-biserial correlation coefficient is used to measure the correlation b/w 2 dichotomous variables

False

The spearman correlation coefficient is used to measure the correlation b/w two nominal variables

False

A correlation of r=.38 in a sample of 30 participants is statistically significant for a two-tailed test at a .05 level of significance

True

Correlation does not show causation

True

Homoscedasticity is the assumption that there is an equal variance of data points dispersed along the regression line

True

If r=.25, then the coefficient of determination is .06

True

The correlation coefficient varies b/w 0 and 1 and can never be negative

false

The Phi correlation coefficient can be converted to a t statistic

true

When we compute many correlations in a single study, we report each correlation coefficient in a table called a correlation matrix

true