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"""
Calculates mean and variance of all features
in the dataset
Args:
X (ndarray): (m, n) Data matrix
Returns:
mu (ndarray): (n,) Mean of all features
var (ndarray): (n,) Variance of all features
"""
, =
### START CODE HERE ###
= 1 / *
= 1 / *
### END CODE HERE ###
return ,
"""
Finds the best threshold to use for selecting outliers
based on the results from a validation set (p_val)
and the ground truth (y_val)
Args:
y_val (ndarray): Ground truth on validation set
p_val (ndarray): Results on validation set
Returns:
epsilon (float): Threshold chosen
F1 (float): F1 score by choosing epsilon as threshold
"""
= 0
= 0
= 0
= / 1000
### START CODE HERE ###
= # Your code here to calculate predictions for each example using epsilon as threshold
= # Your code here to calculate number of true positives
= # Your code here to calculate number of false positives
= # Your code here to calculate number of false negatives
= / # Your code here to calculate precision
= / # Your code here to calculate recall
= 2 * * / # Your code here to calculate F1
### END CODE HERE ###
=
=
return ,