Question

A smog alert is issued when the amount of particulate matter in the air is found to be greater than 7 ppm. Samples collected from 16 stations have a mean of 7.8 ppm and a standard deviation of 2ppm.

d. Perform a post-hoc power analysis. Compute the difference for which you have 80% power witha sample size of n = 16 stations. e. What assumptions have you had to make?

Answer 1

Difference,

We will get an 80% power for the difference of means = 1.3034

Explanation:

R code:

power.t.test(n=16,delta=1.3,sd=2,sig.level = 0.05,power = NULL,type = "one.sample", alternative = "one.sided")

R output

e)

Assumptions to perform one-sample t-test:

1) The sample is randomly and independently selected

2) The population is approximately normally distributed

3) No outlier.