Free Practice Quiz Question List

2 Experimental Design and Variables Online Quiz Questions

Use this free practice quiz with 20 questions to review 2 Experimental Design and Variables, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

A student compares water flow at several faucet openings while keeping water pressure and other relevant conditions consistent. Is a separate control group always necessary for this experiment?

A
True
B
False

Choose one

1 point

In an experiment testing how fertilizer amount affects bean-plant height after four weeks, which factor is the independent variable?

A
The height of the bean plants after four weeks
B
The amount of fertilizer given to each plant
C
The type of soil used
D
The amount of light received

Written response

1 point

A student reads a ruler at an angle while measuring plant height. What category of error does this illustrate?

Fill in the blank

1 point

In a fertilizer experiment, plants receiving no fertilizer serve as the for plants receiving fertilizer.

Choose one

1 point

Which procedure would make a plant-growth experiment easiest for another person to repeat?

A
Write down the expected result but leave out the measurement method
B
Change the measurement time for each group to fit the schedule
C
Specify the materials, steps, measurement method, and number of trials
D
Describe only the factor being changed

True or false

1 point

True or false: Repeating an experiment many times will correct a measurement method that consistently produces biased results.

A
True
B
False

Choose all

1 point

Which practices can help reduce error or make variation in an experiment easier to detect? Select all that apply.

A
Use an appropriate, calibrated measuring tool
B
Change the measurement procedure between groups
C
Follow the same procedure for every group
D
Repeat trials with enough independent samples to reveal variation
E
Discard unexpected results without recording them

Written response

1 point

In an experiment that changes fertilizer amounts and measures bean plants after four weeks, what dependent variable is being measured?

Fill in the blank

1 point

A measured difference supports a conclusion about the changed factor only to the extent that the design controls plausible .

Choose one

1 point

Two groups of bean plants receive different fertilizer amounts, but one group also receives more light. If the groups differ in height, what is the main problem with interpreting the result?

A
The result proves that fertilizer has no effect on plant height
B
The effect of fertilizer cannot be isolated because light also differs between groups
C
Light is the dependent variable because it differs between groups
D
The groups are a valid comparison because both received fertilizer

Open ended

1 point

A researcher wants to compare two treatment groups while limiting the effect of pre-existing differences among samples. Explain how random assignment and repeated trials can help, and identify one problem that repeated trials cannot fix.

Choose one

1 point

A student is comparing plant heights across fertilizer groups. Which measurement plan best reduces procedural differences between groups?

A
Measure each group whenever it is most convenient
B
Give each group a different amount of water to avoid identical conditions
C
Measure all groups at the same time using the same method
D
Change the measurement method after seeing early results

Choose one

1 point

A group discovers that one plant received less water than intended during a trial. What should they do to support an honest interpretation of their results?

A
Remove the affected measurements without noting the change
B
Record the event and any changes made to the procedure
C
Change the results to match the expected pattern
D
Report only the trials that support the prediction

Choose one

1 point

A student changes the amount of fertilizer given to bean plants and measures their height after four weeks. Which measurement is the dependent variable?

A
The amount of fertilizer assigned to each plant
B
The species of bean plant used
C
The height of the plants measured after four weeks
D
The amount of water provided to each plant

Choose one

1 point

A student is comparing fertilizer amounts and wants to reduce alternative explanations for differences in plant height. Which procedure best controls a relevant condition?

A
Use the same soil type for every plant
B
Give each plant a different amount of fertilizer
C
Measure plant height only for the tallest plant
D
Use different plant species in each fertilizer group

Choose one

1 point

In a fertilizer experiment, which group would provide the most meaningful control condition for comparison with fertilized plants?

A
Plants grown in a different soil and given no water
B
Plants given the largest fertilizer amount and more light
C
Plants measured only at the beginning of the experiment
D
Plants given no fertilizer but the same soil, water, light, and care

Written response

1 point

Plants receiving identical treatment still differ in growth because individual plants are not exactly alike. What source of error or variation is this?

True or false

1 point

True or false: Repeating trials will correct a measurement method that consistently reads too high.

A
True
B
False

Choose all

1 point

A researcher wants to test how fertilizer amount and light level affect bean-plant height. Which statements describe a sound approach to this multi-factor investigation? Select all that apply.

A
A single experiment can test more than one factor.
B
The design needs to separate the effects of the factors being tested.
C
Changing two factors together, without separating their effects, identifies which factor caused an observed difference.
D
A multi-factor experiment does not need to measure an outcome.

Written response

1 point

A researcher adds a condition expected to produce a known effect to check whether an experiment’s procedure can detect that effect. What is this type of condition called?