Chapter 9 - Day 5

Overall Notes
• There is one version of this assessment provided in the Teacher Resources Materials (TRM). Use this assessment as-is or use it as a model to create your own.

• If you are making your own assessment, consider using the test bank and the ExamView software.

• Consider allowing students to use the four-step template from this lesson for a significance test.

• After returning graded quizzes to students, consider showing them the 1-PropZTest on the TI 83/84 calculator or using the One sample z test for a proportion applet at www.statsmedic.com/applets

Common Student Errors
• When writing hypotheses for a significance test, students will sometimes incorrectly use notation that refers to a statistic from the sample. Hypotheses should always be written with parameters.

• Students sometimes struggle to identify when an alternative hypothesis is one-sided or two-sided. Encourage them to use clues from the wording of the question.

• When interpreting a P-value, students will forget that it is a conditional probability, where the conditions it that we are "assuming the null hypothesis is true". This must be included in the interpretation of the P-value.

• Students will often forget to include context when interpreting a P-value or when writing a conclusion for a significance test.

• Students will sometimes incorrectly "accept the null", when they should be "failing to reject the null".

• When rejecting the null hypothesis, students will say that we have "proved" the alternative hypothesis is true. We don't know for sure that the alternative is true (we could be making a Type I error), so students should be saying there is "convincing evidence for the alternative hypothesis".

• Students will often confuse the Type I and Type II errors. Remember that for a Type I error, the null is true (and we incorrectly reject the null) and for a Type II error, the alternative is true (and we incorrectly fail to reject the null).

• When checking the Large Counts condition for a significance test, students should be using the null hypothesis value (we assume the null to be true!) and NOT the sample proportion.

• When finding the mean and SD of the sampling distribution for a significance test for a proportion, students should be using the null hypothesis value (we assume the null to be true!) and NOT the sample proportion.

• When using Table A to find the P-value for a one-sided significance test that is shaded to the right, students forget to subtract the Table A value from 1.