(a) A consultant wants to ask workers at a factory about the workers' job satisfaction. Which of the following best describes a random sample of workers?
All of the workers on the second floor of the factory building are easily accessible. So, the consultant selects the first 78
workers from the second floor to arrive at work on a particular day.
The consultant forms groups of 13 workers based on the lengths of time the workers have worked at the factory. Then,
he randomly chooses 6 groups and selects all of the workers in these groups.
The consultant assigns each worker a different number. Using a random number table, he draws 78 of those numbers at
random. Then, the consultant selects the workers assigned to the drawn numbers. Every set of 78 workers is equally
likely to be drawn using the random number table,
(b) A manager at a bus company wants to survey employees about the new uniforms. Which of the following best describes a
stratified sample of employees?
The manager forms groups of 20 employees based on the departments the employees are in. Then, she selects all of the
employees in 4 randomly chosen groups.
The manager uses a computer program to draw 80 employees at random and selects these employees. Every set of 80
employees is equally likely to be drawn by the computer program.
The manager forms 4 groups of employees based on the departments the employees are in. Then, she selects 20
employees at random from each group.
(c) A botanist at a nursery wants to inspect the health of the plants at the nursery. Which of the following best describes a
convenience sample of plants?
All of the plants that are in one particular room at the nursery are easily accessible. So, the botanist selects the 50 plants
in this particular room.
The botanist forms 2 groups of plants based on the ages of the plants (in months). Then, he selects 25 plants at random
from each group.
The botanist takes a list of the plants and selects every 5th plant until 50 plants are selected