Instruction 15-6
Four Surgical Procedures Currently Are Used to Install

question 52

Short Answer

Instruction 15-6
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 centre wants to compare the proportion of clear operations for the four procedures, and collects the following numbers of patients from their own records:
| Procedure |
$$\begin{array} { | l | c | c | c | c | c | } \hline & \text { A } & \text { B } & \text { C } & \text { D } & \text { Total } \\\hline \text { Clear } & 27 & 41 & 21 & 7 & 96 \\\hline \text { Return } & 11 & 15 & 9 & 11 & 46 \\\hline \text { Total } & 38 & 56 & 30 & 18 & 142 \\\hline\end{array}$$ They will use this information to test for a difference among the proportion of clear operations using a chi-square test with a 0.05 level of significance.
-Referring to Instruction 15-6,the value of the test statistic is _______.

---

Definitions:

Stoichiometric Reagents

Chemical substances used in reactions in exact proportions as determined by the reaction equations.

Hazardous Substances

Chemicals or compounds that might pose a risk or cause harm to health, safety, or the environment when improperly handled or released.

Carrying Capacity

The maximum population or load that a particular environment, system, or device can support sustainably.

Sustainability

The practice of maintaining processes or states over time, often specifically in ecological terms, without harmful impact on the natural environment or depletion of resources.