为什么k=5？

问题如下：

To build the training set with 50 defined features, 300 randomly selected working-age clients will be asked a set of open-ended questions by Lucia Fernandez, a market researcher. The resulting answers will include demographic data, information about risk preferences, and other retirement details. A Jubilación analyst will assign each individual in the sample to one of the five portfolios. Martin initially plans to perform machine learning analysis and use the model to assign new clients to the appropriate portfolio based on their responses to the questions.

If Martin were to use a k-nearest neighbor model, the value for k would be closest to:

选项：

5

50

300

解释：

A is correct. Martin wants to classify clients into five different clusters (five strategic investment portfolios), according to the retirement portfolio that is most suitable for their needs.

B is incorrect. 50 is the number of features in the dataset for each interview conducted. These features will be used in the classification process to determine which portfolio is most suitable.

C is incorrect. 300 is the number of interviews conducted, not the number of clusters into which these 300 observations will be sorted.