Question

A researcher considers two methods for collecting data to determine if store-brand laundry detergents work as well as name-brand detergents.


Method 1: The researcher surveys shoppers as they enter a grocery store. The shoppers are asked which type of detergent they use and then rate the cleanliness of their laundry on a scale from 1 to 10 (with 10 being the cleanest). The ratings of the name-brand detergents are compared to the ratings of the store-brand detergent.


Method 2: The researcher creates 10 loads of soiled fabrics and washes 5 of the loads with name-brand detergent and the other 5 with store-brand detergent. Volunteers are asked to assess the cleanliness of the fabrics using a scale from 1 to 10 (with 10 being the cleanest), and the ratings of the name-brand detergents are compared to the ratings of the store-brand detergent.


Which method describes an observational study?


Method 2 is an observational study because volunteers assess the fabrics.

Method 1 is an observational study because many people can be surveyed.

Method 1 is an observational study because no attempt is made to influence results.

Both methods are observational studies because information on both types of detergent can be collected.


Not A.

Answer 1

This question is solved understanding the concepts of experimental and observational studies.

Doing this, we have that the correct answer is given by option: Method 1 is an observational study because no attempt is made to influence results.

First, we present the concepts:

• Experimental study: In an experimental study, there is an intervention in a sample, and it's effect is studied.
• Observational study: In an observational study, the sample is just analyzed, without any intervention.

In this question:

• Method 1: The shoppers are just surveyed, and the results are computed, no intervention, so it is an observational study.
• Method 2: 5 of the loads are washed, which consists in an intervention, thus, it is an experimental study.

Thus, method 1 describes an observational study, as no attempt is made to influence results.

For more on experimental/observational studies, you can check https://brainly.com/question/23214549

Answer 2

Answer:

C. Method 1 is an observational study because no attempt is made to influence results.

Step-by-step explanation: