Reference no: EM132409017

In August 2003, 56% of all employed adults in the United States reported that basic mathematical skills were critical or very important to their job. A researcher believes that this proportion has increased, so a random sample of 480 employed adults was taken and 297 of them felt that basic mathematical skills are critical or very important to their job. Be sure to check if the conditions are met, and show how you checked them - show ALL work.

1a) Is there sufficient evidence to conclude that the percentage of all employed adults who feel basic mathematical skills are critical or very important to their job has increased? Use a significance level of α =0.05. 

Whats your conclusion?

1b) Find a 90% confidence interval for the proportion of all employed adults in the United States who feel that basic mathematical skills are critical or very important to their job. State your answer in words:

1c) How large of a sample would be needed in order to have a margin of error E=3% and a confidence level of 98%? sample size n=?