Question

4. Let’s assume a researcher is creating a sampling distribution for the exam scores of introduction to marketing course finals for the last 10 years that were taken at Wayne State University. Let’s us assume that the sample size is 225.What is the standard error? How do we interpret that number?

5. Let’s now estimate the population mean with a 95% level of confidence. In other words, compute a range such that you are 95% confident that this range will include the true population parameter.

Answer 1

(4)

(i)

Given:

n = Sample Size = 225

Let

= Standard Deviation of the population of the exam scores of introduction to marketing course finals for the last 10 years that were taken at Wayne State University

From the given data, let

= Sample Mean

Standard Error (SE) is given by:

(ii)

Interpretation:

   indicates that the sampling distribution of sample means is distributed as normal distribution with mean = mean of the population = and standard deviation given by

(5)

= 0.05

From Table, critical values of Z = 1.96.

Confidence Interval:

The 95% Confidence Interval: is a range of values we are 95% certain will contain the unknown true population mean.