Ch. 5 | Exercise 2

# Chapter 5 | Exercise 2

Create a bar plot with the 95% confidence intervals around the means of the imagery scores for the high- and low-frequency nouns in the data frames `pym_high` and `pym_low`. Is there a substantial overlap between the confidence intervals?

First, load the package and the data sets if you have not done so yet.

```> library(Rling) > data(pym_high) > data(pym_low) > se.high <- sd(pym_high\$imag)/sqrt(length(pym_high\$imag)) #SE for high-frequency nouns > se.low <- sd(pym_low\$imag)/sqrt(length(pym_low\$imag)) #SE for low-frequency nouns > ci.upper.high <- mean(pym_high\$imag) + 1.96*se.high #upper boundary of CI for high-frequency nouns > ci.lower.high <- mean(pym_high\$imag) - 1.96*se.high #lower boundary of CI for high-frequency nouns > ci.upper.low <- mean(pym_low\$imag) + 1.96*se.low #upper boundary of CI for high-frequency nouns > ci.lower.low <- mean(pym_low\$imag) - 1.96*se.low #lower boundary of CI for high-frequency nouns > ci.lower <- c(ci.lower.high, ci.lower.low) > ci.upper <- c(ci.upper.high, ci.upper.low) > means <- c(mean(pym_high\$imag), mean(pym_low\$imag)) #means > library(gplots) > barplot2(means, plot.ci = TRUE, ci.l = ci.lower, ci.u = ci.upper, main = "Bar plot with 95% confidence intervals", xlab = "Frequency groups", ylab = "Average imagery scores", names = c("High","Low")) ```

The bar plot shows that the 95% confidence intervals overlap to a large extent.