Which of the following is a common method to detect heteroskedasticity?

Plotting residuals against fitted values

Computing the skewness of the dependent variable

Checking the correlation between independent variables

Calculating the mean of the residuals

A quality control engineer is analyzing the diameter of manufactured ball bearings. The diameters are normally distributed with a mean of 10 mm and a standard deviation of 0.2 mm. The engineer needs to find the probability that a randomly selected ball bearing has a diameter between 9.8 mm and 10.2 mm. Which approach is correct?

Calculate the PMF at 9.8 and 10.2 and add them

Calculate the CDF at 10.2 and subtract the CDF at 9.8

Subtract the mean from 10.2 and divide by the standard deviation

A data team is building a churn prediction model for a telecom company. The dataset contains 20% churned customers and 80% non-churned. The team wants to ensure that the test set accurately reflects the overall churn rate so that evaluation metrics are reliable. Which technique should the team apply when splitting the data?

Clustering customers by tenure before splitting

Stratified sampling based on the churn label

Oversampling the churned customers in the test set

Simple random sampling without replacement

A data scientist is working on a credit card fraud detection model. Fraudulent transactions are rare, making up only 0.5% of the data. The scientist wants to improve the recall of the fraud class. Which technique is most directly aimed at this goal?

Oversampling the fraud class using SMOTE

Increasing the number of features in the model

Removing all non-fraudulent transactions

Stratifying the training set by transaction amount

CompTIADataX

Domain 1Objective 2

Probability and Modeling DY0-001 Practice Questions (Page 1)

Part of the Mathematics and statistics domain, which accounts for 17% of the DY0-001 exam. CompTIA does not publish an official question count, but from its 165-minute exam (~65–110 total, ~11–19 in this domain), expect 3–5 from this objective — we provide 31 practice questions to prepare you well beyond it. (estimate)

31questions here

7free pages

10concepts

17%of the exam

Questions 1–5

1foundation · easy
Which of the following is a common method to detect heteroskedasticity?
Select an answer first
2application · medium
A quality control engineer is analyzing the diameter of manufactured ball bearings. The diameters are normally distributed with a mean of 10 mm and a standard deviation of 0.2 mm. The engineer needs to find the probability that a randomly selected ball bearing has a diameter between 9.8 mm and 10.2 mm. Which approach is correct?
Select an answer first
3application · medium
A data scientist is analyzing the waiting time at a restaurant. The waiting time follows an exponential distribution with a mean of 10 minutes. The scientist wants to find the probability that a customer waits more than 15 minutes. Which calculation is correct?
Select an answer first
4application · medium
A data team is building a churn prediction model for a telecom company. The dataset contains 20% churned customers and 80% non-churned. The team wants to ensure that the test set accurately reflects the overall churn rate so that evaluation metrics are reliable. Which technique should the team apply when splitting the data?
Select an answer first
5application · medium
A data scientist is working on a credit card fraud detection model. Fraudulent transactions are rare, making up only 0.5% of the data. The scientist wants to improve the recall of the fraud class. Which technique is most directly aimed at this goal?
Select an answer first

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Probability and Modeling DY0-001 Practice Questions (Page 1)

Questions 1–5

Which of the following is a common method to detect heteroskedasticity?

A data scientist is analyzing the waiting time at a restaurant. The waiting time follows an exponential distribution with a mean of 10 minutes. The scientist wants to find the probability that a customer waits more than 15 minutes. Which calculation is correct?

A data scientist is working on a credit card fraud detection model. Fraudulent transactions are rare, making up only 0.5% of the data. The scientist wants to improve the recall of the fraud class. Which technique is most directly aimed at this goal?

Keep studying — Mathematics and statistics