A Researcher Wanted to Determine If Using an Octane Booster $X _ { 1 }$

question 92

Multiple Choice

A researcher wanted to determine if using an octane booster would increase gasoline mileage. A random sample of seven cars was selected; the cars were driven for two weeks without the booster and two weeks with the booster. Use the definitions of $X _ { 1 }$ and $X _ { 2 }$ as given in the table. Consequently, $D = X _ { 1 } - X _ { 2 }$ .


What critical value should be used at $\alpha = 0.05 ?$

• A) -1.943
• B) -2.447
• C) -2.365
• D) -1.895

---

Definitions:

Serta Mattress

A brand of mattresses known for their comfort and quality, often highlighted in discussions about sleep improvement and home furnishing.

Pillow-Top

A type of mattress featuring an additional upholstery layer on the top for enhanced comfort, often used in descriptions of bedding products.

Preconscious Level

A psychological term for thoughts and feelings not immediately in consciousness but that can easily be brought to mind.

Need Awareness

The recognition by consumers that they have a specific unmet need.