# R/deltaR2.R In dstanley4/apaTables: Create American Psychological Association (APA) Style Tables

#### Defines functions get_deltaR2_ciget_sr2_ci

```get_sr2_ci <- function(sr2, R2, n, conf_level) {
R2_2 <- R2
R2_1 <- R2-sr2
ci <- get_deltaR2_ci(R2_2 = R2_2,R2_1=R2_1,n=n, conf_level = conf_level)
return(ci)
}

get_deltaR2_ci <- function(R2_2,R2_1,n,conf_level=.95){
#Alf Jr, E. F., & Graf, R. G. (1999). Asymptotic confidence limits for the difference between two squared multiple correlations: A simplified approach. Psychological Methods, 4(1), 70.
#Case 2 from paper

z <- qnorm((1-((1-conf_level)/2)))

r20A <- R2_2
r20B <- R2_1

r0A  <- sqrt(r20A)
r0B  <- sqrt(r20B)

rAB  <- r0B/r0A
r2AB <- rAB^2

var_delta_r2 <- (4*r20A*(1-r20A)^2)/n + (4*r20B*(1-r20B)^2)/n - 8*r0A*r0B*(.5*(2*rAB-r0A*r0B)*(1-r20A - r20B - r2AB)+rAB^3)/n

LL <- (r20A -r20B) - z*sqrt(var_delta_r2)
UL <- (r20A -r20B) + z*sqrt(var_delta_r2)

output <- list()
output\$LL <- LL
output\$UL <- UL
return(output)
}
```
dstanley4/apaTables documentation built on Oct. 21, 2018, 11:36 p.m.