What does the probability density function (PDF) describe for a continuous random variable?

The probability that the variable falls within a specific interval

The cumulative probability up to a point

The exact probability of a single value

The probability of each discrete outcome

Which type of missing data occurs when the probability of missingness is unrelated to any variable in the dataset?

Missing completely at random (MCAR)

A data scientist is fitting a linear regression model to predict energy consumption based on temperature. After fitting the model, the scientist plots the residuals versus the fitted values and observes a funnel shape: the residuals are tightly clustered at low fitted values but spread widely at high fitted values. The scientist is considering: (A) transforming the dependent variable using a log transformation, or (B) using weighted least squares. Which approach is more directly aimed at addressing the observed pattern?

Only A, because the log transformation is the only way to fix heteroskedasticity

Both A and B can address heteroskedasticity, but the log transformation is often simpler and can stabilize variance

Neither A nor B, because heteroskedasticity cannot be corrected

Only B, because weighted least squares is the only valid method

Which of the following is an example of a discrete random variable?

The time it takes to complete a task

The height of a randomly selected person

The number of customers arriving at a store in an hour

In a negatively skewed distribution, which of the following is typically true?

The mean is greater than the median.

The mean is less than the median.

CompTIADataX

Domain 1Objective 2

Probability and Modeling DY0-001 Practice Questions (Page 6)

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 26–30

26foundation · easy
What does the probability density function (PDF) describe for a continuous random variable?
Select an answer first
27foundation · easy
Which type of missing data occurs when the probability of missingness is unrelated to any variable in the dataset?
Select an answer first
28expert · hard
A data scientist is fitting a linear regression model to predict energy consumption based on temperature. After fitting the model, the scientist plots the residuals versus the fitted values and observes a funnel shape: the residuals are tightly clustered at low fitted values but spread widely at high fitted values. The scientist is considering: (A) transforming the dependent variable using a log transformation, or (B) using weighted least squares. Which approach is more directly aimed at addressing the observed pattern?
Select an answer first
29foundation · easy
Which of the following is an example of a discrete random variable?
Select an answer first
30foundation · easy
In a negatively skewed distribution, which of the following is typically true?
Select an answer first

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