An Internet Service Provider (ISP) Has Randomly Selected a Sample

question 35

Multiple Choice

An internet service provider (ISP) has randomly selected a sample of 223 observations concerning values of the response variable Churn and several predictor variables based on customer activity during the most recently billed month. Here Churn equals Yes if a customer churned-left the internet service provider for another ISP-and equals No otherwise. The predictor variable MinutesOn is the average daily minutes the customer spent online. EmailSent is the average daily number of emails the customer sent from the email address provided by the ISP. ServCalls is the number of times the customer called for service. Below is part of the classification tree they derived from the data collected in the study. Of the sampled customers who spent an average of at least 511 minutes online per day and sent an average of fewer than 7 emails per day from their ISP-provided email address, how many churned?

• A) 7
• B) 8
• C) 9
• D) 14
• E) 32

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Definitions:

Expected Value

The long-run average value of repetitions of the experiment it represents, often used in probability and statistics.

Shopping Outlet

A retail store or set of stores where products are sold directly to the public, often at reduced prices.

Covariance

A measure of the degree to which two variables change together, indicating the direction of their linear relationship.

Coefficient of Correlation

A statistical measure that calculates the strength and direction of a linear relationship between two variables on a scatter diagram.