Databricks Certified Professional Data Scientist Exam - Topic 5 Question 4 Discussion

Actual exam question for Databricks's Databricks Certified Professional Data Scientist exam

Question #: 4
Topic #: 5

[All Databricks Certified Professional Data Scientist Questions]

The figure below shows a plot of the data of a data matrix M that is 1000 x 2. Which line represents the first principal component?

Ayellow

Bblue

CNeither
Principal component analysis (PCA) involves a mathematical procedure that transforms a number of (possibly) correlated variables into a (smaller) number of uncorrelated variables called principal components. The first principal component
accounts for as much of the variability in the data as possible, and each succeeding component accounts for as much of the remaining variability as possible.
The first principal component corresponds to the greatest variance in the data. The blue line is evidently this first principal component, because if we project the data onto the blue line, the data is more spread out (higher variance) than if projected
onto any other line, including the yellow one.

Show Suggested Answer

Suggested Answer: B

by Jesusa at May 05, 2022, 04:18 PM

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Azalee

4 months ago

I don't know, this seems too straightforward.

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Maybelle

4 months ago

Totally agree, blue is the one!

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Brande

4 months ago

Wait, are we sure it's not the yellow line?

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Afton

4 months ago

Definitely the blue line!

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Lynelle

5 months ago

The first principal component shows the highest variance.

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Daren

5 months ago

I'm a bit confused about how to visually determine the first principal component. Is it always the line that looks the steepest?

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Dalene

5 months ago

I think the blue line looks like it could be the first principal component since it seems to spread the data out more.

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Kandis

5 months ago

I remember that the first principal component should capture the most variance, but I'm not entirely sure which line that is in this plot.

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Shawna

5 months ago

I practiced a similar question where the principal component was the line that best fits the data spread. I hope that helps here!

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Myrtie

5 months ago

Manually replacing the Host Encryption Key (HEK) of each affected host seems like the most straightforward approach to me.

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Crissy

5 months ago

Hmm, I'm not sure about that. I was thinking we might need to use GROUP BY and HAVING to filter for subscribers with more than one purchase.

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Stevie

5 months ago

I seem to remember the trend being a slight decrease overall, which might point to that 23 percent option? But I really can't be confident on this one.

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