# SADC Course in Statistics Revision on tests for means using CAST (Session 17)

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SADC Course in Statistics Revision on tests for means using CAST (Session 17)

To put your footer here go to View > Header and Footer 2 Learning Objectives By the end of this session, you will be able to discuss the different approaches used in dealing with independent and paired samples for comparing means explain how you will decide when to use a one-sided test and when to use a two-sided test appreciate how the evidence against the null hypothesis becomes stronger as the difference between the two means increases

To put your footer here go to View > Header and Footer 3 Using CAST for SADC: Higher Level Further insight into the concepts introduced in sessions 12 and 13 can be obtained by working through some of the pages of CAST in Sections 7.4 and 7.5 Practical work using CAST will therefore form the main activity in this session Here we will just highlight a few of the features that the above pages in CAST aim to demonstrate

To put your footer here go to View > Header and Footer 4 CAST – Section 7.4 Consider CAST Section 7.4: Hypothesis test for difference This section has 3 sub-sections as follows: Testing a hypothesis One-tailed tests Exercises about tests We briefly outline below what each section contains. This is aimed at reminding you of the key ideas involved.

To put your footer here go to View > Header and Footer 5 CAST – Section 7.4 – Page 1 This sections is aimed at showing the development of a test for testing whether 2 group means are equal. There is a choice of 4 data sets you might use for this purpose. There is also a simulation exercise designed to emphasise that even when H 0 is true, it is still possible to get a significant result 5% of the time when testing at a 5% level of significance.

To put your footer here go to View > Header and Footer 6 CAST – Section 7.4 – Page 2 This sections is aimed at distinguishing between a 1-tailed and 2- tailed test. This choice is important and you will be given examples that help you to understand the difference. Again a simulation exercise is included to illustrate the ideas involved.

To put your footer here go to View > Header and Footer 7 CAST – Section 7.4 – Page 3 This section gives some exercises. It gives you practice in doing 1-tailed and 2-tailed tests for testing the difference between two population means.

To put your footer here go to View > Header and Footer 8 CAST – Section 7.5 Consider CAST Section 7.5: Paired Data This section has 4 sub-sections as follows: Paired data Analysis of differences Paired t-test Pairing and experimental design We look at each in turn and also remind you of the key ideas involved.

To put your footer here go to View > Header and Footer 9 CAST – Section 7.5 – Pages 1 and 2 These sections are aimed at explaining what pairing is providing a range of different examples to illustrate the ideas emphasising the need to compute and analyse differences between paired values Can you remember why pairing is done? What is the benefit of pairing?

To put your footer here go to View > Header and Footer 10 CAST – Section 7.5 – Pages 3 and 4 These sections are aimed at explaining the testing approach with paired samples demonstrating how the evidence against the null hypothesis increases as the difference between the means of the two populations increases using a simulation exercise to help distinguish between independent and paired samples.

To put your footer here go to View > Header and Footer 11 Practical work on CAST follows…