Experimental Design, Scientific Questions, and Variables

Flashcards covering observational versus experimental studies, formulating testable scientific questions, and defining independent, dependent, and controlled variables.

In an experimental study, the researcher manipulates the sample population and re-measures using the same procedures to determine if the manipulation possibly changed the __________.

measurements

In an observational study, data is simply gathered without experimental manipulation, and __________ are investigated.

correlations

During a controlled experiment, all groups are manipulated in some manner except for the __________, which remains the same.

control group

A weakness or restriction in the design of an experiment that may limit the applicability of results is defined as a __________.

limitation

In a 2001 report in the Journal of the American Cancer Institute, findings comparing night-shift work and breast cancer risk were based on the work histories of $763$ women with breast cancer and __________ women without the disease.

$$741$$

In a study examining the effects of dietary patterns on blood pressure in $459$ subjects, those fed a diet low in fat and cholesterol lowered their systolic blood pressure by an average of __________ points compared to the control diet.

$$6.7$$

The first step scientists take when narrowing down a broad question into a testable experiment is identifying what __________ they need.

background information

When formulating a specific testable question from a broad topic, the question should identify what to change, what to measure, and what to __________.

study

According to the Scientific Question Checklist, a testable question must identify something the experimenter can change or manipulate and something they can observe or __________.

measure

In the example of narrowing down a broad question about acid rain affecting the environment, the specific factor chosen to be changed was the __________ of the water.

acidity

The independent variable is the factor changed on purpose by the experimenter, also known as the __________ variable.

manipulated

The dependent variable is measured because it changes in response to the independent variable, and is sometimes called the __________ variable.

responding

In an experiment testing different conditions, a negative control group serves as an untreated or '__________' group.

always off

In an investigation testing how exercise affects heart rate, using the exact same heart rate monitor for each measurement is an example of a __________ variable.

controlled