Experimental Design

On what axis should the independent variable always be?

• X
• Y

Which statement is best supported by the data in the chart?

• After exercise, the nonathletic students had a lower heart rate than the athletic students.

• After exercise, the heart rates of the athletic students returned to resting pulse in four minutes.

• During exercise, both groups of students had the same increase above their resting pulse.

• During exercise, the athletic students had a higher heart rate than the nonathletic students.

Which activity most likely corresponds to the pulse rate of the person while sleeping?

• 1

• 2

• 3

• 4

An experiment is carried out to determine how different pH values of soil will affect the growth of tomato plants. In this experiment, the dependent variable could be the

• height of the tomato plants

• pH of the soil

• specific variety of tomato plants used

• pH of enzymes in tomato leaf cells

An observation that deals with measurements or numbers.

• quantitative observation

• qualitative observation

• data

• information

A student is opening and closing clothespins as part of a lab activity. The student begins to experience muscle fatigue, and the rate at which the student is opening and closing the clothespins slows. Which graph best represents the relationship between time and number of clothespin squeezes?

• 1

• 2

• 3

• 4

Which statement is best supported by the data in the chart?

• After exercise, the nonathletic students had a lower heart rate than the athletic students.

• After exercise, the heart rates of the athletic students returned to resting pulse in four minutes.

• During exercise, both groups of students had the same increase above their resting pulse.

• During exercise, the athletic students had a higher heart rate than the nonathletic students.

An observation made using only the senses.

• Quantitative observation

• Qualitative observation

• Data

• Inference

Before watching a scary movie, the members of a theater audience agreed to have their heart rates monitored. They were asked to sit in silence for 10 minutes before the film began. The movie was then shown from beginning to end. The scatter plot summarizes the data collected by all of the heart monitors from ten minutes before the start of the movie to the end of the movie.

Which is a possible hypothesis most likely being tested in this experiment?

• Silence in a theater increases the heart rates of the audience

• The length of a movie causes changes in heart rate

• Do heart rates increase while watching scary movies?

• Watching scary movies will increase the heart rates of audience members

One student checks his pulse and counts 23 beats over a time interval of 20 seconds. In which row in the data table should the pulse rate of this student be recorded?

• A

• B

• C

• D