(This article was first published on

**Jeromy Anglim's Blog: Psychology and Statistics**, and kindly contributed to R-bloggers)This post sets out how to calculate confidence intervals for correlations using R. Because I often get this question from people unfamiliar with R, it assumes no prior knowledge of R.

### Formulas

- Online Statsbookhas formulas for calculating the confidence interval of a correlation coefficient.

### R

Download and Install R (R Home Page; Windows Installation)

Start R and run the following commands, updating the

`CIr`

command as required:

`install.packages("psychometric") # install package with function`

library(psychometric) # load package with function

# The following command calculates lower and upper

# 95% confidence intervals (level)

# assuming sample size (n) is 100

# and the obtained correlation (r) is 0.90

CIr(r=.9, n = 100, level = .95)

To

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