I only need part d In this problem you are going to analyze

I only need part d.

In this problem you are going to analyze the built-in R data set iris. First, extract the sepal
width of the virginica species and save it to a vector x using this command:
x = iris$Sepal.Width[iris$Species == \"virginica\"]

Answer the following:
(a) R Code: Using a Gaussian approximation, what is the 95% confidence interval for the
mean of x?
(b) R Code: Using a Student t distribution, what is the 95% confidence interval for the
mean of x?
(c) R Code: Now assume that you only have the first 10 measurements. That is, create
the vector
y = x[1:10]. Repeat parts (a) and (b) for the vector y.
(d) How did the decrease in sample size affect the results? Were the two different confidence
intervals affected differently?

Solution