A Cell Phone Service Provider Has Selected a Random Sample

question 47

Multiple Choice

A cell phone service provider has selected a random sample of 20 of its customers in an effort to estimate the mean number of minutes used per day. The results of the sample included a sample mean of 34.5 minutes and a sample standard deviation equal to 11.5 minutes. Based on this information, and using a 95 percent confidence level:

• A) the critical value is z = 1.96
• B) the critical value is z = 1.645
• C) the critical value is t = 2.093
• D) The critical value can't be determined without knowing the margin of error.

---

Definitions:

Goals and Dreams

Aspirations or desired outcomes that individuals aim to achieve in the future.

Transformational Leadership

A leadership approach that causes change in individuals and social systems, inspiring followers to exceed their own interests for the good of the group.

Work Group Effectiveness

The measure of how successfully a group achieves its goals, maintains its social well-being, and adapts to changes.

Brain Research

The study of the brain's structure, function, and development to understand behavior and cognitive processes.