A Tutor Promises to Improve GMAT Scores of Students by More

question 34

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 is the correct value of the test statistic?

• A) z = 1.7143
• B) z = 1.7500
• C) t₄₈ = 1.7143
• D) t₄₈ = 1.7500

Comprehend the significance of selecting appropriate smoothing parameters in exponential smoothing.

Understand the basic concepts of time series analysis including its definition and components.

Distinguish between the different types of moving averages.

Identify and explain the four components of time series: trend, cyclical, seasonal, and random variations.