A manager at a bus company wants to survey employees about the new uniforms. Which of the following best describes a random sample of employees? The manager asks for volunteers and selects every volunteer until 72 employees are selected. She selects the volunteers because these employees are easily accessible. The manager forms groups of 8 employees based on the departments the employees are in. Then she selects all of the employees in randomly chosen groups. The manager uses a computer program to draw 72 employees at random and selects these employees. Every set of 72 employees is equally likely to be drawn by the computer program.
A botanist at a nursery wants to inspect the health of the plants at the nursery. Which of the following best describes a stratified sample of plants? The botanist assigns each plant a different number. Using a random number table, he draws 78 of those numbers at random. Then, he selects the plants assigned to the drawn numbers. Every set of 78 plants is equally likely to be drawn using the random number table. The botanist forms groups of 13 plants based on the heights of the plants. Then, he randomly chooses 6 groups and selects all of the plants in these groups. The botanist forms groups of plants based on the ages of the plants (in months). Then, he selects 13 plants at random from each group.
A consultant wants to ask workers at a factory about their job satisfaction. Which of the following best describes a convenience sample of workers? The consultant forms 6 groups of workers based on the workers' shifts. Then, he selects 9 workers at random from each group. All of the workers on the second floor of the factory building are easily accessible. The consultant selects the first 54 workers from the second floor to arrive at work on a particular day. The consultant takes a list of the workers and selects every 6th worker until 54 workers are selected.