Dell EMC Data Science and BigData Certification Questions and Answers

Question : Refer to the exhibit.
You are using K-means clustering to classify customer behavior for a large retailer. You need to
determine the optimum number of customer groups. You plot the within-sum-of-squares (wss)
data as shown in the exhibit. How many customer groups should you specify?

1. 2
2. 3
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4. 8



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Question : Refer to the exhibit.
Click on the calculator icon in the upper left corner. You are given a list of pre-defined association
rules:
A) RENTER => BAD CREDIT
B) RENTER => GOOD CREDIT
C) HOME OWNER => BAD CREDIT
D) HOME OWNER => GOOD CREDIT
E) FREE HOUSING => BAD CREDIT
F) FREE HOUSING => GOOD CREDIT
For your next analysis, you must limit your dataset based on rules with confidence greater than
60%.
Which of the rules will be kept in the analysis?


1. Rules B and D
2. Rules A and F
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4. Rules D and E



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Question : Refer to the exhibit.
You are using k-means clustering to discover groupings within a data set. You plot within-sum-ofsquares
(wss) of multiple cluster sizes. Based on the exhibit, how many clusters should you use in
your analysis?

1. 2
2. 8
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4. 10



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Related Questions

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Question : What is an example of a null hypothesis?


1. that a newly created model provides a prediction of a null sample mean
2. that a newly created model does not provide better predictions than the currently existing model
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4. that a newly created model provides a prediction that will be well fit to the null distribution


Question : You have fit a decision tree classifier using input variables. The resulting tree used of the
variables, and is 5 levels deep. Some of the nodes contain only 3 data points. The AUC of the
model is 0.85. What is your evaluation of this model?


1. The tree did not split on all the input variables. You need a larger data set to get a more accurate model.
2. The AUC is high, and the small nodes are all very pure. This is an accurate model.
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4. The AUC is high, so the overall model is accurate. It is not well-calibrated, because the small nodes will give poor estimates of probability.



Question : If your intention is to show trends over time, which chart type is the most appropriate way to depict the data?


1. Line chart
2. Bar chart
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4. Histogram



Question : You are analyzing a time series and want to determine its stationarity. You also want to determine
the order of autoregressive models.
How are the autocorrelation functions used?


1. PACF as an indication of stationarity, and ACF for the correlation between Xt and Xt-k not
explained by their mutual correlation with X1 through Xk-1.
2. ACF as an indication of stationarity, and PACF to determine the correlation of X1 through Xk-1.
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4. ACF as an indication of stationarity, and PACF for the correlation between Xt and Xt-k not
explained by their mutual correlation with X1 through Xk-1.



Question : Which word or phrase completes the statement? A spreadsheet is to a data island as a centralized
database for reporting is to a ________?


1. Data Repository
2. Analytic Sandbox
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4. Data Warehouse


Question : Which R data structure allows elements to have different data types?


1. Matrix
2. Vector
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4. Array