rdif.nul {psychometric}

Null hypothesis for difference in two correlations

Description

Tests the hypothesis that two correlations are significantly different

Usage

rdif.nul(r1, r2, n1, n2)

Arguments

r1

Correlation 1

r2

Correlation 2

n1

Sample size for r1

n2

Sample size for r2

Details

First converts r to z' for each correlation. Then constructs a z test for the difference z <- (z1 - z2)/sqrt(1/(n1-3)+1/(n2-3))

Value

Returns a table with 2 elements

zDIF

z value for the H0

p

p value

Note

Does not test alternate hypotheses (e.g., difference = .1)

Author(s)

Thomas D. Fletcher [e-mail]

References

Cohen, J., Cohen, P., West, S. G., & Aiken, L. S. (2003). Applied multiple regression/correlation analysis for the behavioral sciences (3rd ed.). Mahwah, NJ: Lawrence Erlbaum.

See Also

r.nil, CIrdif

Examples

# From ch. 2 in Cohen et al (2003)
rdif.nul(.657, .430, 62, 143)