A doubt in C1_W2 Lecture

Course Q&A Machine Learning Specialization Supervised ML: Regression and Classification
1

Dear Administrator,

Could you please guide me on this issue?

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image1136×375 54.4 KB

I have a question on this contour plot. Shouldn’t the parameter b represents the vertical axis while the vector of w represents the horizontal axis?

From what I have learned in the Week 1 Lecture, creating a contour plot for cost function J(w,b) will have a result of the parameter w represents the horizontal axis and the parameter b represents the vertical axis.

May I know the reason of w2 represents the vertical axis?

Thank you.

The picture is taken from this learning material:

Supervised Machine Learning: Regression and Classification

  • Gradient descent in practice
    • Video: Feature scaling part 1
      • Time-> 4:31/6:34
2

We can plot J, w, and b but it will be 3D. For simplicity, Prof. Andrew drew a 2D plot.

3

Dear Mr Saifkhanengr,

According to the contour plot, there are J, w1, and w2 but b is missing.

May I know the reason of w2 represents the vertical axis but not b?

Thank you.

4

‘b’ is not important for the purposes of this 2D plot that shows the contour plots.
‘b’ is a constant (a bias) that is added to every example.

What’s more significant is the impact of having two features.

5

Thank you so much Mr TMosh for your guidance.