Question

1. luisa hypothesized that she was more likely to get a “heads” result whenever she flipped a coin rather than a “tails” result. she tested her hypothesis by flipping a quarter 20 times and recording her results. she then flipped a different quarter 20 times and recorded those results. flipping two different coins multiple times is an example of which of the following? a. analyzing data b. repeating trials c. making inferences d. replicating an experiment 8. aarti was studying the effect of gravitational force on falling objects. she decided to compare two balls made of the same material. one ball was smaller than the other. which of the following steps should she take to be sure her data is accurate? a. perform multiple trials. b. write down her steps. c. make a prediction before starting. d. make sure the color of the balls is the same. 9. danielle designed an experiment to test the effectiveness of a new brand of fertilizer for houseplants. she potted two identical plants in identical pots with the same type of potting soil. she added the recommended amount of fertilizer to one plant, using the other plant as her control. the plants were given equal amounts of sunlight and water each day. she measured the plants’ height every two days. after 10 days, she concluded that the fertilizer improved plant growth. how could danielle have changed her design to include repeated trials? a. tested two different levels of fertilizer b. measured plant height every day for 10 days c. used four plants instead of one for each treatment d. measured plant height every other day for 20 days

Explanation:

• For question 7: Repeating trials involves conducting the same experiment multiple times with the same or similar conditions. Luisa flipping two different coins multiple times is an example of repeating trials. Analyzing data comes after trials are done, making inferences is drawing conclusions from data, and replicating an experiment is done by another researcher following the same procedure.
• For question 8: Performing multiple trials helps to ensure the accuracy of data in an experiment. Writing down steps is good for documentation but doesn't directly ensure data accuracy. Making a prediction is part of the scientific - method but not for ensuring data accuracy. The color of the balls is not relevant to the study of gravitational force on falling objects.
• For question 9: Repeated trials involve increasing the sample size for each treatment group. Using four plants instead of one for each treatment (fertilized and non - fertilized) is an example of adding repeated trials. Testing different levels of fertilizer is about variable manipulation, measuring plant height more frequently or for a longer time is about data collection frequency and duration.

Answer:

1. B. repeating trials
2. A. Perform multiple trials.
3. C. used four plants instead of one for each treatment