AP Stats SRL 2/12/21

_________ is a sample in which each individual or object in the entire population has an equal chance of being selected.

• Sample
• Population
• Random Sample
• Quartile

Kim surveys 100 moviegoers that entered the movie theater in the first hour.  What type of sampling method is this?

• Random
• Convenience
• Biased

A school randomly chose ten English teachers and asked them which type of juice their students would prefer. Which reason best shows why this sample is biased?

• The sample didn't include students.
• The sample is too small.
• The sample can only be accurate if each teacher is included in the sample

a controlled study in which the researcher attempts to understand cause-and-effect relationships by assigning subjects to groups and deciding which treatments each group receives

• survey

• observational study

• experiment

You want to see if students who have a 4.0 grade point average study more than those who do not.

• survey

• observational study

• experiment

A large company wants to conduct a survey to determine the proportion of its male employees who practice yoga on a daily basis. Two of its regional offices are chosen at random and all of the male employees at each office are surveyed. The plan is an example of which type of sampling?

• Cluster

• Convenience

• Simple random

• Stratified random

• Systematic

Every possible group of units of the required size has the same chance of being the selected sample as any other sample of the same size.

• Simple Random 
• Thoughtful
• Typical
• Proportional

This sample is selected by dividing the population into subgroups and then taking a fixed number of units from each group using the simple random sample.

• stratified
• cluster
• judgment
• experimental

In a certain school, students can choose whether to eat in the school’s cafeteria. A reporter working for the school’s newspaper polled students on their reactions to changes in the menu at the cafeteria. For each student leaving the cafeteria in one 20-minute time period, the reporter used a die to determine whether to stop the student and ask how he or she felt about the new menu. In the reporter’s article it was stated that a random sample of the students showed that 23% of the school’s student population was happy with the new menu. Which of the following statements is true?

• Because each student leaving the cafeteria was randomly selected and could choose to answer or not, this is a random sample of the student population, and the 23% is an accurate measurement of the school population’s view of the new menu.

• Because students self-selected whether to eat in the cafeteria, the sampling method might be biased and the sample might not be representative of all students in the school.

• The survey would have been more effective if the reporter had collected the data in one 10-minute time period rather than in one 20-minute time period.

• The survey would have been more effective if students who cared about the food could have called the reporter to tell how they felt about the new menu, so that only students with opinions on the subject would have been surveyed.

• Because no treatment was imposed on the students eating in the cafeteria, one cannot make any conclusions about the new menu.

To check the effect of hot temperatures on the elasticity of two brands of rubber bands, one box of Brand A and one box of Brand B rubber bands are tested. Ten bands from the Brand A box are placed in a warm car in the sun for two hours and ten bands from the Brand B box are kept at room temperature. The amount of stretch before the breakage is measured on each rubber band, and the mean for the hot bands is compared to the mean for the others. Is this a good experimental design?

• No, because the means are not proper statistics for comparison.

• No, because more than two brands should be used.

• No, because more temperatures should be used.

• No, because temperature is confounded with brand.

• Yes