Databricks Certified Professional Data Scientist Exam - Topic 4 Question 31 Discussion

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

Question #: 31
Topic #: 4

[All Databricks Certified Professional Data Scientist Questions]

While working with Netflix the movie rating websites you have developed a recommender system that has produced ratings predictions for your data set that are consistently exactly 1 higher for the user-item pairs in your dataset than the ratings given in the dataset. There are n items in the dataset. What will be the calculated RMSE of your recommender system on the dataset?

Dn/2
The root-mean-square deviation (RMSD) or root-mean-square error (RMSE) is a frequently used measure of the differences between values predicted by a model or an estimator and the values actually observed. Basically, the RMSD represents the sample standard deviation of the differences between predicted values and observed values. These individual differences are called residuals when the calculations are performed over the data sample that was used for estimation, and are called prediction errors when computed out-of-sample. The RMSD serves to aggregate the magnitudes of the errors in predictions for various times into a single measure of predictive power. RMSD is a good measure of accuracy, but only to compare forecasting errors of different models for a particular variable and not between variables, as it is scale-dependent. RMSE is calculated as the square root of the mean of the squares of the errors. The error in every case in this example is 1. The square of 1 is 1 The average of n items with value 1 is 1 The square root of 1 is 1 The RMSE is therefore 1

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Suggested Answer: A

by Yolando at Oct 11, 2022, 08:48 PM

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Lisha

4 months ago

Not sure, feels like there’s more to it than just that.

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France

4 months ago

Yup, RMSE is definitely 1 here.

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Shaniqua

4 months ago

Wait, how can it be that consistent? Seems off.

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Otis

4 months ago

Totally agree, it’s just 1 higher for every rating.

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Mozell

4 months ago

RMSE will be 1, simple math!

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Lynna

5 months ago

I'm a bit confused about how the number of items, n, plays into the RMSE calculation here. Does it change the outcome?

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Isreal

5 months ago

I practiced a similar question where the predictions were consistently off by a fixed amount, and I think it led to the same RMSE result.

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Rolland

5 months ago

I think if the predictions are always 1 higher, the error for each prediction is just 1, so the RMSE should be 1, right?

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Jolene

5 months ago

I remember that RMSE is calculated by taking the square root of the average of the squared differences, but I'm not entirely sure how the constant error affects it.

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Nieves

5 months ago

I've got this one! The standard record type used to create a forecast in Dynamics 365 Sales is the Opportunity. Opportunities are where you track potential sales, so that's the logical choice for forecasting revenue. I'm confident in this answer.

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Leonardo

5 months ago

Okay, I've got this. Governance and management objectives are high-level, so they're not just about a single process or component. They're about a group of related processes that work together to achieve the objective. The answer has to be A.

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Audria

5 months ago

Okay, let me think this through step-by-step. The yield curve shows the relationship between yields and the term or maturity of the bonds. So the correct answer must be A, yield against term.

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Holley

5 months ago

Hmm, I'm a bit unsure about this one. Changing the IP address should be simple, but the fact that the engineer can't ping the new address makes me think there's something else missing. I'll have to think this through step-by-step.

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Alverta

5 months ago

I have a vague recollection of a client engagement letter including similar statements about compliance, but I doubt that's the right answer for this question.

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