Chapter 9 - Day 8

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.

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".

• When checking the Normal/Large Sample condition for the case of small sample size and no knowledge of the population distribution, students should include a sketch of a graph for the sample data.

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

• Students will incorrectly use z-scores and Table A, when they should be using t-scores and Table B.

• When using Table B for a df that is not on the table, students should use the df that is the next lowest one.