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.

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Note for This Quiz

• We did not have students calculate standard deviation for a discrete random variable using the formula. Instead, we provided them with the standard deviation and asked them to interpret. 

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Common Student Errors

• When calculating probabilities for a discrete random variable, students often struggle with choosing the right boundary value. For example “less than 3” is P(X<3) while “at most 3” is P(X<=3). Be sure students understand the meaning of “at least”, “at most”, “more than”, and “less than”. 

• Students often struggle finding probabilities for a uniform distribution. Remind them that the total area for the rectangle is 1, which will often help them to find the height (probability) for the rectangle. 

• When students are finding the area to the right of a value in a normal distribution, they often forget to subtract the Table A value from 1. A picture will always help with this, as students can look at their final answer and see if it is reasonable based on the picture they drew. 

• When interpreting the mean and standard deviation for a discrete random variable, students will sometimes forget to give context, saying something like “the values typically vary”.