A Bank Is Trying to Determine Which Model of Safe

question 131

Multiple Choice

A bank is trying to determine which model of safe to install. The bank manager believes that each model is equally resistant to safe crackers but sets up a test to be sure. He hires nine safe experts to break into each of the models, timing each endeavor. The results (in seconds) are given next, paired by expert. Let D be the difference: Time to break Safe 1 minus Time to break Safe 2. Which of the following hypotheses will determine if the two safes take, on average, the same amount of time to crack?

• A) H₀: µ_D ≤ 0, H_A: µ_D > 0
• B) H₀: µ_D ≥ 0, H_A: µ_D < 0
• C) H₀: µ_D ≠ 0, H_A: µ_D = 0
• D) H₀: µ_D = 0, H_A: µ_D ≠ 0

Discuss the concept and importance of random assignment in experimental designs.

Recognize the features and implications of within-subjects vs. between-subjects experimental designs.

Identify methods to mitigate weaknesses in posttest-only and pretest-posttest control group designs.

Understand the principles and guidelines for developing reliable and valid scale items.

---

Definitions:

Hypertension

Sustained, above normal, mean arterial blood pressure.

Diabetes Mellitus

A chronic condition characterized by high levels of sugar in the blood due to the body's inability to produce or properly use insulin.

Cardiovascular Disease

A class of diseases that involve the heart or blood vessels, including coronary artery disease, heart failure, and stroke.

Inferior Vena Cava

A large vein that carries deoxygenated blood from the lower and middle parts of the body back to the right atrium of the heart.