Lesson 13: What Makes a Good Sample? | Unit 8: Probability and Sampling

Open Ended

Suppose 45% of all the students at Andre’s school brought in a can of food to contribute to a canned food drive. Andre tries to pick a representative sample of 25 students from the school. He will calculate the percentage of the sampled students who brought in canned food. He expects the percentage for this sample will be 45%. Do you agree? Explain your reasoning.

Open Ended

The three dot plots together are the scores of teenagers in three samples from this population. Which of the three samples is most representative of the population? Explain how you know.

Multiple Choice

This is a dot plot of the number of text messages sent one day for a sample of the students at a local high school. The sample consists of 30 students and is selected to be representative of the population. What do the six values of 0 in the dot plot represent?

• The six values of 0 represent six students who sent one text message each.
• The six values of 0 represent six students who sent more than ten text messages.
• The six values of 0 represent six students who sent an average of five text messages.
• The six values of 0 represent six students who sent no text messages.

Multiple Choice

This is a dot plot of the number of text messages sent one day for a sample of the students at a local high school. The sample consists of 30 students and is selected to be representative of the population. Since this sample is representative of the population, what might a dot plot for the entire population look like?

• The population dot plot would have a peak at 90 messages sent.
• The population dot plot would likely mirror the sample, showing a concentration of low text message counts with a gradual decline as the number of messages increases.
• The population dot plot would show a uniform distribution of text messages sent.
• The population dot plot would only display high text message counts with no low counts.