Question(a) 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 forms groups of 8 plants based on the heights of the plants. Then, he randomly chooses 7 groups and selects all of the plants in these groups.
The botanist forms 7 groups of plants based on the ages of the plants (in months). Then, he selects 8 plants at random from each group. The botanist assigns each plant a different number. Using a random number table, he draws 56 of those numbers at random. Then, he selects the plants assigned to the drawn numbers. Every set of 56 plants is equally likely to be drawn using the random number table, (b) A chemist at a pharmaceutical company wants to test the quality of a new batch of microscopes. Which of the following best describes a systematic sample of microscopes?
The chemist forms 5 groups of microscopes based on the prices of the microscopes. Then, he selects 18 microscopes at random from each group. The microscopes in the first shipment that was received are easily accessible. So, he selects all 90 of the microscopes in this shipment. The chemist takes a list of the microscopes and selects every $5^{\text {th }}$ microscope until 90 microscopes are selected. (c) A facilities supervisor at a sports stadium wants to rate the condition of the seats at the stadium. Which of the following best describes a random sample of seats? The supervisor uses a computer program to draw 64 seats at random and selects these seats. Every set of 64 seats is equally likely to be drawn by the computer program. The supervisor takes a list of the seats and selects every $4^{\text {th }}$ seat until 64 seats are selected. The supervisor forms groups of 8 seats based on the sections the seats are in. Then, she selects all of the seats in 8 randomly chosen groups.