A Tutor Promises to Improve GMAT Scores of Students by More

question 11

Multiple Choice

A tutor promises to improve GMAT scores of students by more than 50 points after three lessons.To see if this is true,the tutor takes a sample of 49 students' test scores after and before they received tutoring.The mean difference was 53 points better after tutoring,with a standard deviation of the difference equal to 12 points.Let µ_D denote the mean of the difference: score after tutoring minus score before tutoring.Which of the following hypotheses will determine if the students improved their test scores by more than 50 points after being tutored?

• A) H₀: µ_D ≤ 0,H_A: µ_D > 0
• B) H₀: µ_D ≥ 0,H_A: µ_D <0
• C) H₀: µ_D ≤ 50,H_A: µ_D >50
• D) H₀: µ_D ≥ 50,H_A: µ_D <50

---

Definitions:

Public Story

A narrative crafted for or shared in a public domain, often influencing public perception or community identity.

Obsessive Relational Intrusion

Unwanted and invasive behaviors by one individual towards another in attempts to establish or restore intimacy.

Non-Threatening Invasion

An approach or action that enters someone's personal space in a manner perceived as safe or non-intimidating.

Acquaintance

A person one knows slightly, but who is not a close friend.