Scientific Method Regents Review

A biologist in a laboratory reports a new discovery based on experimental results. If the experimental results are valid, biologists in other laboratories should be able to

• repeat the same experiment with a different variable and obtain the same results.

• perform the same experiment and obtain different results.

• repeat the same experiment and obtain the same results.

• preform the same experiment under different experimental conditions and obtains the same results.

A mineral supplement designed to prevent the flu was given two groups of people during a scientific study. Dosages of the supplement were measured in milligrams per day, as should in the table below.

After 10 weeks, neither group reported a case of the flue. Which procedure would have made the outcome of this study more valid.

• test only one group with 100 mg of the supplement

• test the supplement on both groups for 5 weeks instead of 10 weeks

• test a third group that receives 150 mg of the supplement

• test a third group that does not receive the supplement

Tags

NGSS.MS-ETS1-1

A biologist formulates a hypothesis, performs experiments to test his hypothesis, makes careful observations, and keep accurate records of his findings. In order to complete this process, the biologist should

• adjust the data to support the hypothesis

• eliminate data that do not support the hypothesis

• write a research paper explaining his theories before performing his experiment, in order to gain funding sources

• evaluate the findings and, if necessary, alter the hypothesis based on his findings, and test the new hypothesis

An investigation was carried out to determine which of three antibacterial soaps is most effective. Four petri dishes labeled A, B, C, and D were set up. The same amount and type of bacteria was added to each dish. Next, 2mL of a different brand of soap were added to dishes B, C, and D. Then, 2mL of water were added to dish A, instead of soap. The dishes were incubated at 37° C for 24 hours. At the end of the investigation, the amount of bacteria in each dish was determined. Dish D had the least bacteria. It was concluded that the soap in dish D was the most effective soap to use against bacteria. Which statement best describes the validity of this conclusion?

• The conclusion is not valid since the same amount of bacteria was used in each dish.

• The conclusion is valid since too small a sample of bacteria was used in this investigation.

• The conclusion is valid since the amounts of bacteria were measured at the end of the investigation.

• The conclusions might not be valid since the investigation was carried out only once.

Tags

NGSS.MS-PS1-2

Reasons for conducting peer review include all of the following except

• analyzing the experimental design

• pointing out possible bias

• identifying an illogical conclusion

• changing data to support the hypothesis

An experimental design included references from prior experiments, materials and equipment, and step-by-step procedures. What else should be included before the experiment can be started?

• a set of data

• a conclusion

• safety precautions to be used

• an inference based on results

A student hypothesized that lettuce seeds would not germinate (begin to grow) unless they were covered with soil. The student planted 10 lettuce seeds under a layer of soil and scattered 10 lettuce seeds on top of the soil. The data collected are shown in the accompanying table.

To improve the reliability of these results, the student should

• conclude that darkness is necessary for lettuce seed germination

• conclude that light is necessary for lettuce seed germination

• revise the hypothesis

• repeat the experiment using a large sample size

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-1

An analysis of data gathered during a particular experiment is necessary in order to

• formulate a hypothesis for that experiment

• develop a research plan for that experiment

• design a control for that experiment

• draw a valid conclusion for that experiment

A student conducted an experiment to determine if listening to different types of music would affect pulse rate. She thought that pulse rate would change with different types of music. Each person participating in her experiment listened to seven different selections of music for 30 seconds each. The pulse rates were taken on her experiment, the student concluded that a person's pulse rate changed when listening to different types of music.

The component missing from this experiment is a

• prediction

• hypothesis

• control group

• research plan

A student was comparing preserved specimens of three plant species, X, Y, and Z, in a classroom. Which statement is an example of an observation the student could have made and not an inference?

• the leaves produced by plant X are 4 cm across and 8 cm in length.

• plant Y has a large purple flowers that open at night.

• plant X produces many seeds that are highly attractive to finches.

• the flowers of plant Z are poisonous to household pets.