Concept #1: Calculating the Large Sample Test Statistic of a Sample Mean

Concept #2: Calculating the Large Sample Test Statistic of a Sample Mean: Intro

Practice: Speed limits aren't as black and white as officials would like. A random sample of 64 cares on a 55-mph highway revealed an average speed of 60mph with a standard deviation of 36mph. Is there enough evidence to claim that drivers are driving faster than the speed limit at 2% significance level?

Practice: The average lifespan in Europe was 90-years-old in 2010. A random sample fo 81 cases of death revealed an average age of 94 with a standard deviation of 13.5 years. Can we say that European life-span has changed since 2010 using an alpha = .10?

Practice: A graduate school claims to only admit students who receive a 1200 or higher on the GRE. A random sample of 100 graduates students within the university revealed a mean of 1150, with a standard deviation of 140. Test to see that the average GRE score for admitted graduate students is at least 1200 using a 1% significance level.