Question

after researching the possible effects of music, elaina proposes that if people listen to faster - paced music, their pulse rates will increase more than if they listen to slower music. her mother quietly listens to classic rock at a high volume for 30 minutes, her younger brother listens to classical music while he sleeps at night, and her grandmother listens to two hours of rap at a medium volume. elaina records each persons pulse before and after listening to the music.
what can you infer is missing from elainas scientific investigation?
a a testable hypothesis naming independent and dependent variables
b an experiment that takes initial and final measurements
c controlled variables with only one varied independent variable
d experimental data that can be recorded and analyzed
question 8 (4 points)
(dt.01 hc)
in a magazine advertisement, a manufacturer claims its laundry ball, which contains ceramic pellets, gets clothes clean by changing the ph of the water. the ad claims the product reduces wear on clothing, contaminants in the environment, and the cost of doing laundry. what should the advertisement include to give a consumer more confidence in this products claims?
a information about product testing in a study that includes a control group
b a lack of testimony from users who have used the product for several months
c pictures comparing loads of laundry cleaned with and without the product
d information about how the product benefits the environment

Explanation:

For the first question:

• Elaine's experiment has multiple variables (music type, volume, listening time) not controlled. In a proper experiment, only the independent variable (music pace in her hypothesis) should vary while others are controlled.
• Option a: She has a testable hypothesis (if faster - paced music, then pulse rate increase).
• Option b: She takes initial and final pulse measurements.
• Option d: She records data (pulse before and after).

For the second question:

• A study with a control group (e.g., laundry without the ball vs with the ball) provides scientific evidence.
• Option b: Lack of user testimony is not helpful.
• Option c: Pictures can be misleading.
• Option d: Just info on environmental benefit without testing proof is weak.

Answer:

First question: C. Controlled variables with only one varied independent variable
Second question: A. Information about product testing in a study that includes a control group