Well, think about internal -- it means within. Therefore, "internal conflict" is conflict within the mind (can't make up a decision, etc.) and external conflict means conflict on the outside (fist fights, etc.). He doesn't trust himself, so that takes place within his own mind, so it's internal conflict.
Explanation: in literature, a conflict is a struggle between opposite forces, usually between a character (the main character or a very important one) and himself (internal conflict), society or another character (external conflict). In the given scenario we can see an example of an internal conflict, because the signalman doesn't trust himself (he isn't in conflict with anyone else but himself).
<h3><u><em>Perhaps the most common goal in statistics is to answer the question: Is the variable X (or more likely, X 1 , ... , X p ) associated with a variable Y, and, if so, what is the relationship and can we use it to predict Y?
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<h3><em>Nowhere is the nexus between statistics and data science stronger than in the realm of prediction—specifically the prediction of an outcome (target) variable based on the values of other “predictor” variables. Another important connection is in the area of anomaly detection, where regression diagnostics originally intended for data analysis and improving the regression model can be used to detect unusual records. The antecedents of correlation and linear regression date back over a century.</em></h3>
