TABLE 2- 5
the Following Are the Durations in Minutes

question 38

Multiple Choice

TABLE 2- 5
The following are the durations in minutes of a sample of long-distance phone calls made within the continental United States reported by one long-distance carrier.
$$\begin{array}{l}\begin{array} { l l } \hline&\text { Relative}\\\text { Time (in Minutes) }&\text {Frequency }\\\hline0 \text { but lessthan } 5 & 0.37 \\5 \text { but less than } 10 & 0.22 \\\text { 10 but lessthan } 15 & 0.15 \\\text { 15 but less than } 20 & 0.10 \\\text { 20 but lessthan } 25 & 0.07 \\\text { 25 but lessthan } 30 & 0.07 \\30 \text { or more } & 0.02 \\\hline\end{array}\end{array}$$
-Referring to Table 2-5, if 100 calls were randomly sampled, how many calls lasted 15 minutes or longer?

• A) 14
• B) 74
• C) 26
• D) 10

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Definitions:

Ex Post Facto Design

Ex Post Facto Design is a research approach where investigators study variables after the events have occurred, analyzing the effects of naturally occurring differences without manipulation.

Correlational Study

A research method that examines the relationship between two or more variables to determine if a change in one is associated with a change in others.

Retrospective Study

A research design that looks back in time to analyze data from past records to investigate a particular outcome or phenomenon.

Prospective Study

A research design that follows participants forward in time to examine the relationship between specific exposures and outcomes.