TABLE 12-9
Four Surgical Procedures Currently Are Used to Install

question 74

True/False

TABLE 12-9
Four surgical procedures currently are used to install pacemakers. If the patient does not need to return for follow-up surgery the operation is called a "clear" operation. A heart center wants to compare the proportion of clear operations for the 4 procedures, and collects the following numbers of patients from their own records:
$$\begin{array}{l}\text {\quad\quad\quad\quad\quad\quad\quad Procedure }\\\begin{array} { l | r r r r | r } & \text { A } & \text { B } & \text { C } & \text { D } & \text { Total } \\\hline \text { Clear } & 27 & 41 & 21 & 7 & 96 \\\text { Return } & 11 & 15 & 9 & 11 & 46 \\\hline \text { Total } & 38 & 56 & 30 & 18 & 142\end{array}\end{array}$$ They will use this information to test for a difference among the proportion of clear operations using a chi-square test with a level of significance of 0.05.
-Referring to Table 12-9, there is sufficient evidence to conclude that the proportions between procedure A and procedure D are different at a 0.05 level of significance.

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Definitions:

Gills

Respiratory organs in certain aquatic organisms, allowing them to extract oxygen from water.

Gases

Substances that are in the state of matter characterized by having neither a defined volume nor shape, expanding to fill their container.

Terrestrial

Terrestrial refers to things relating to the Earth or living or growing on land as opposed to water or air.

Aquatic Environments

Natural water bodies like rivers, lakes, and oceans that are habitats for a wide range of organisms.