Instruction 15-8
Four Surgical Procedures Currently Are Used to Install

question 5

Short Answer

Instruction 15-8
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 |
$$\begin{array} { | l | c | c | c | c | c | } \hline & \mathrm { A } & \mathrm { B } & \mathrm { C } & \mathrm { D } & \text { Total } \\\hline \text { Clear } & 27 & 41 & 21 & 7 & 96 \\\hline \text { Return } & 11 & 15 & 9 & 11 & 46 \\\hline \text { Total } & 38 & 56 & 30 & 18 & 142 \\\hline\end{array}$$ 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 15-8,the overall or mean proportion of clear operations is ________.

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Definitions:

Scramble Competition

See Exploitation Competition.

Intraspecific

Pertaining to interactions or relationships occurring within the same species, such as competition or mating.

Negative Feedback

A regulatory mechanism in which a stimulus causes an opposite output in order to maintain an optimal level of whatever is being regulated.

Density Dependent

Factors whose effects on the size or growth of the population vary with the population density.