A Tutor Promises to Improve GMAT Scores of Students by More

question 21

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. Assuming α = 0.05, which of the following is the appropriate critical value?

• A) z = 1.677
• B) z = 2.011
• C) t_0.05,48 = 1.677
• D) t_0.05,₄₈ = 2.011

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Definitions:

Division Revenues

The total income generated from the sales of goods or services by a specific division or segment of a larger company.

Profit Centers

Divisions or branches of a company that are directly responsible for generating its profits, tracked separately to evaluate performance.

Discretion

The ability or authority to make decisions and choices based on one's own judgment.

Corporate Executives

Senior management or high-level officers in a corporation who are responsible for making company-wide decisions.