Welcome to STAT 2023 Spring 2018!

Greetings Students!

Welcome to STAT 2023, Elementary Statistics for Business and Economics.

This website provides homework assignments, keys to exercises for examples, and past exams with keys.   The material can be very helpful to you to study, learn, and practice the concepts of statistics.  The first class period will cover how the aspects of the course fit together and will discuss a plan for success.

Let’s have a great semester!

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Summary Page for Exam Three review

Here is the summary page with the basic equations for Inferences on the parameters known as the population mean and population proportion.  Summary Lessons 13, 14, 15, 16 Inferences on Mean and Proportion

Four Extra Credit Assignments

There are four 4-point extra credit assignments available on the Assignments Page.  These points will go on top of your class total points.

Z and t hypothesis tests and confidence intervals

The detailed class notes that we viewed in class are here:   Class Notes Z test and t test, with CI equations .

Compare the Z and t distributions

On Tuesday, October 24, 2017, STAT 2023 began to consider Inferences on the Population Mean when the Population Standard Deviation is known.  The resulting hypothesis test and confidence interval are based on the Z-distribution, also called the Standard Normal Distribution.  On Tuesday, October 31, 2017, STAT 2023 began to consider Inference on the Population Mean when the Population Standard Deviation is unknown.   The sample standard deviation, S, will be used as an estimator for sigma, the population standard deviation, but when that occurs the test statistic is not Z, but t and the confidence interval form is also based on t, not Z.   Here are some details, Class Notes Z test and t test, with CI equations .