Question

select the correct answer from each drop-down menu.

a researcher is examining the claims made by a water softener salt manufacturer. he performs an experiment using water from a variety of sources. for each water source, he has a sample with no treatment and a sample treated with the recommended amount of the water softener salt.

he then tests each sample to measure the softness and compares the results, determining that the claims made by the manufacturer are true.

the conclusion drawn from the study is valid/invalid because the sample is biased/unbiased. in this instance, an experimental/observational study was performed.

Explanation:

Identify the study design

The researcher actively applies a treatment (the water softener salt) to one group of samples and leaves another group untreated (control) to observe the effects. This manipulation of variables defines an experimental study rather than an observational study.

Evaluate the validity and bias

The researcher uses water from a variety of sources, testing both a treated and an untreated sample for each source. This paired design controls for the source of water, making the sample representative and unbiased. Thus, the conclusion drawn is valid because the sample is unbiased.

Determine the study type appropriateness

Since the researcher wants to test the causal claim made by the manufacturer, performing an experiment with a control group and a treatment group is the correct methodology. Therefore, an appropriate study was performed.

Answer:

Select the correct answer from each drop-down menu.

A researcher is examining the claims made by a water softener salt manufacturer. He performs an experiment using water from a variety of sources. For each water source, he has a sample with no treatment and a sample treated with the recommended amount of the water softener salt.

He then tests each sample to measure the softness and compares the results, determining that the claims made by the manufacturer are true.

The conclusion drawn from the study is <blank>valid</blank> because the sample is <blank>unbiased</blank>. In this instance, an <blank>appropriate</blank> study was performed.