Question

Using R, Suppose you are reading a study on egg mass in lizards. The authors state, "Average egg mass (mg) (+/- Standard Error) is 27.1 (1.1), based on a sample size of 100 eggs." Based upon this information, if you were to sample an additional 100 eggs from this population, what interval would you expect 95% of these eggs to fall between?

Answer 1

R code:

m=2.71
n=200
se=1.1/sqrt(2)
round(m-qt(1-0.025,199)*se,4) #Lower boundary
round(m+qt(1-0.025,199)*se,4) #Upper boundary

Output:

> round(m-qt(1-0.025,199)*se,4) #Lower boundary
[1] 1.1762
> round(m+qt(1-0.025,199)*se,4) #Upper boundary
[1] 4.2438