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.

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Definitions:

Psychodynamic

A perspective in psychology that emphasizes the systematic study of the psychological forces that underlie human behavior, feelings, and emotions and how they might relate to early experience.

Neo-analytic

Pertains to a school of thought in psychology that revises and expands upon Freudian and pre-Freudian psychoanalytic theories, emphasizing social and cultural factors more.

Repression

A defense mechanism where distressing thoughts, memories, or desires are excluded from the conscious mind.

Defense Mechanism

Psychological strategies employed unconsciously to protect oneself from anxiety arising from unacceptable thoughts or feelings.