PMA 3 (2022-23)

A scientist wants to get the most accurate results for his experiment, so he does multiple trials and averages the result. This is an example of

• redundancy

• replication

• replacement

• repetition

A scientist wants to determine which fertilizer is more effective—Fertilizer X or Fertilizer Y. The best way for her to proceed would be to design an experiment with

• two groups of plants—a group fertilized by X and a control group with no fertilizer.

• three groups of plants—a group fertilized by X, a group fertilized by both X and Y, and a control group with no fertilizer.

• two groups of plants—a group fertilized by Y and a control group with no fertilizer.

• three groups of plants—a group fertilized by X, a group fertilized by Y, and a control group with no fertilizer.

A student is conduction an experiment to see how watering schedule affects the growth of grass. He conducts the experiment two times. His data are different each time, and he comes to two different conclusions. What should he do next?

• forget about the entire investigation

• get different kinds of plants and start over

• repeat the experiment carefully one or more times

• change the results so that they match

Vanessa is conducting an experiment to see how exposure to different types and amounts of light affects the growth of plants. Her results are shown in the data table below. Did Vanessa make an error in the design of her experiment?

• No; Vanessa designed her experiment correctly.

• Yes; Vanessa should have measured with customary units.

• Yes; plants cannot grow in artificial light.

• Yes; there are too many manipulated variables in her experiment.

A student sets up an experiment to see how sunlight affects how tall a plant grows. She gives two identical plants the same amount of water every day, but she puts one plant in sunlight and the other plant in shade. Which of the follwoing is the dependent variable?

• plant location

• amount of water given to each plant

• time of the year

• plant height

Which statement is correct?

• An experiment should have only one variable that changes at a time

• An experiment begins with drawing a conclusion and ends with asking a question

• Doing an experiment does not include recording data and drawing a conclusion

• You can make up an experiment as you go along

Use the HR-diagram below to answer the following question.

Which of the following statements accurately describes one of the stars in the HR diagram?

• Star A is the brightest star

• Star B is a red star

• Star C is the dimmest star

• Star D is the hottest star

Destiny was looking at different stars in the night sky with her telescope and noticed that some stars were red while other stars were blue. What answer choice below best describes why a star would appear to have a different color?

• Blue stars are hotter than red stars.

• Red stars are hotter than blue stars.

• Blue stars are closer to Earth than red stars.

• Red stars are closer to Earth than blue stars.

The table below compiles information about two stars. What statement explains the difference between how Sirius and Betelgeuse appear from

Earth?

• Sirius appears brighter because it is closer to Earth.

• Betelgeuse appears brighter because it is closer to Earth.

• Sirius appears brighter because it has a greater absolute brightness.

• Betelgeuse appears brighter because it has a greater absolute brightness.

The diagram below shows a person standing between two stars of the same size, color, and brightness. The person states that Star A looks brighter than Star B. What is the person describing?

• sequence

• temperature

• absolute brightness

• apparent magnitude