Adaface Sample Machine Learning Questions

You are working on a regression problem using a simple neural network. You want to optimize the model's weights using gradient descent with different learning rate schedules. Consider the following pseudo code for training the neural network:

Which of the following learning rate schedules would most likely result in the fastest convergence without overshooting the optimal weights?
            
            A: Constant learning rate of 0.01
            B: Exponential decay with initial learning rate of 0.1 and decay rate of 0.99
            C: Exponential decay with initial learning rate of 0.01 and decay rate of 0.99
            D: Step decay with initial learning rate of 0.1 and decay rate of 0.5 every 100 epochs
            E: Step decay with initial learning rate of 0.01 and decay rate of 0.5 every 100 epochs
            F: Constant learning rate of 0.1

You are given a dataset to solve a classification problem using a decision tree algorithm. You are concerned about overfitting and decide to implement pruning to control the model's complexity. Consider the following pseudo code for creating the decision tree model:

Which of the following combinations of parameters would result in a less complex decision tree model, reducing the risk of overfitting?
            
            A: max_depth=5, min_samples_split=2, min_samples_leaf=1
            B: max_depth=None, min_samples_split=5, min_samples_leaf=5
            C: max_depth=3, min_samples_split=2, min_samples_leaf=1
            D: max_depth=None, min_samples_split=2, min_samples_leaf=1
            E: max_depth=3, min_samples_split=10, min_samples_leaf=10
            F; max_depth=5, min_samples_split=5, min_samples_leaf=5

Our newest machine learning developer want to write a function to calculate the n-gram of any text. An N-gram means a sequence of N words. So for example, "black cats" is a 2-gram, "saw black cats" is a 3-gram etc. The 2-gram of the sentence "the big bad wolf fell down" would be [["the", "big"], ["big", "bad"], ["bad", "wolf"], ["wolf", "fell"], ["fell", "down"]]. Can you help them select the correct function for the same?

You are tasked with building a recommendation system for a newly launched e-commerce website. Given that the website is new, there is not much user interaction data available. Also, the items in the catalog have rich descriptions. Based on these requirements, which type of recommendation system approach would be the most suitable for this task?

You have trained a supervised learning model to classify customer reviews as either "positive" or "negative" based on a dataset with 10,000 samples and 35 features, including the review text, reviewer's name, and rating. The dataset is split into a 7,000-sample training set and a 3,000-sample test set.
            
            After training the model, you evaluate its performance using a confusion matrix on the test set, which shows the following results:

Based on the confusion matrix, what are the sensitivity and specificity of the model?