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

question 58

Multiple Choice

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,which of the following tests will be the most appropriate to find out which of the four procedures is the most effective?

• A)The Marascuilo procedure.
• B)X² test for difference in proportions.
• C)Z for difference in proportions.
• D)None of the above.

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Definitions:

Research Hypothesis

Statement regarding an expected or predicted relationship between variables.

Ordinal Variables

Variables that represent categories with a natural order or ranking, but where the distances between categories are not necessarily equal.

Spearman Rank-Order

A nonparametric measure of rank correlation that assesses how well the relationship between two variables can be described using a monotonic function.

Pearson Correlation

A measure of the linear correlation between two variables X and Y, giving a value between -1 and 1 which indicates the extent of their linear relationship.