TABLE 12-9
Four Surgical Procedures Currently Are Used

question 135

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, the decision made suggests that the 4 procedures all have different proportions of clear operations.

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The degree of power held by a singular entity to control prices or exclude competition within a market.

Natural Monopoly

A market condition where a single firm can supply a good or service to an entire market more efficiently than multiple firms due to high fixed or startup costs.

Economies Of Scale

The cost advantage that arises with increased output of a product, as fixed costs are spread over more units of production, reducing the cost per unit.