AP Test Preview - Collecting Data

Staff members of a high school newspaper want to obtain an estimate of the average number of years teachers in the state have been teaching. At an educational conference attended by many teachers in the state, the staff members randomly selected 50 conference attendees and asked the attendees how long they have been teaching. Which of the following describes the sample and the population to which it would be most reasonable for the staff members to generalize the results?

• The sample is the 50 conference attendees, and the population is all teachers in the state.

• The sample is the 50 conference attendees, and the population is all conference attendees.

• The sample is all conference attendees, and the population is all teachers in the state.

• The sample is all conference attendees, and the population is the 50 conference attendees.

• The sample is the average number of years that all conference attendees have taught, and the population is all conference attendees.

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

Measurements of water quality were taken from a river downstream from an abandoned chemical dumpsite. Concentrations of a certain chemical were obtained from 9 measurements taken at the surface of the water, 9 measurements taken at mid-depth of the water, and 9 measurements taken at the bottom of the water. What type of study was conducted, and what is the response variable of the study?

• An experiment was conducted, and the response variable is the concentration of the chemical.

• An experiment was conducted, and the response variable is the depth of the water.

• A census was conducted, and the response variable is the depth of the water.

• An observational study was conducted, and the response variable is the concentration of the chemical.

• An observational study was conducted, and the response variable is the depth of the water.

Tags

CCSS.HSS.IC.B.3

A study was conducted to evaluate the impact of taking a nutritional supplement on a person’s reaction time. One hundred volunteers were placed into one of three groups according to their athletic ability: low, moderate, or high. Participants in each group were randomly assigned to take either the nutritional supplement or a placebo for six weeks. At the end of the six weeks, participants were given a coordination task. The reaction time in completing the task was recorded for each participant. The study compared the reaction times between those taking the supplement and those taking the placebo within each athletic ability level. Which of the following is the best description of the study?

• A randomized block design

• A completely randomized design

• A matched-pairs design

• A randomized observational study

• A stratified observational study

Tags

CCSS.HSS.IC.B.3

A program that was intended to cure a person’s fear of spiders was offered at a local zoo. Volunteers with

a fear of spiders participated in the program, which included holding a spider for 15 minutes. One month after

they completed the program, the participants were contacted and surveyed about the program. Over 90 percent of the participants claimed they were cured of their fear of spiders. Based on the description of the program,

which of the following statements is true?

• Because over 90% of the participants claimed to be cured, the results prove that holding a spider will cure a person’s fear of spiders.

• Because over 90% of the participants claimed to be cured, the results can be generalized to the population of all people who have a fear of spiders.

• Because the participants were volunteers, the study is a census of all people in the local area who have a fear of spiders.

• Because the participants were self-selected, a person’s desire to be cured could be a confounding variable.

• Because participants held a spider for 15 minutes, the study is an experiment and the results can be generalized to the population of all people who have a fear of spiders.

Tags

CCSS.HSS.IC.B.3

An agricultural scientist wanted to compare the effect of a new fertilizer to that of three older fertilizers—X, Y,

and Z—on the growth of vegetables typically grown in small gardens. Two hundred green bean seedlings were

individually planted in identical pots and randomly assigned to one of four groups of 50 each. Seedlings in one

group were given the new fertilizer, and the three remaining groups of seedlings were given fertilizers X, Y, or

Z, respectively. At the end of four weeks, all seedlings were dried and weighed. The scientist found that the

mean weight of the seedlings in the group given the new fertilizer was significantly greater than the mean

weights of seedlings in the other three groups. The scientist concluded that the new fertilizer was more effective

than the other fertilizers for all vegetables. Why is the scientist’s conclusion not appropriate?

• The study was observational, so cause and effect cannot be concluded.

• The study was observational, so no replication was used in the study.

• The experiment only included green beans, so the results cannot be generalized to all vegetables.

• The experiment did not group the seedlings into blocks by the variety of beans.

• The experiment lacked a control group that did not use any fertilizer.

Tags

CCSS.HSS.IC.B.3