A data scientist is modeling the time between customer service requests at a call center. The requests arrive independently, and the scientist needs to calculate the probability that the next request arrives within the next 3 minutes. The scientist has already fitted a continuous probability distribution to the inter-arrival times. Which function should the scientist use directly to answer this question?

Integrate the probability mass function (PMF) from 0 to 3

Evaluate the cumulative distribution function (CDF) at 3 minutes

Evaluate the probability density function (PDF) at 3 minutes

Compute the mean of the distribution and divide by 3

What is stratification in the context of statistical sampling?

Choosing samples based on convenience

Dividing the population into homogeneous subgroups and sampling from each subgroup

Selecting every nth item from a list

Taking a simple random sample from the entire population

What does kurtosis measure in a probability distribution?

The heaviness of the tails and the peakedness of the distribution

The asymmetry of the distribution

The central tendency of the distribution

What does the probability mass function (PMF) provide for a discrete random variable?

The cumulative probability up to a value

The density of values in an interval

The probability of each possible value

The average value of the variable

A data analyst is modeling the number of defects per batch of products. The analyst finds that the number of defects follows a binomial distribution with n=10 trials and p=0.2. What is the probability of observing exactly 3 defects in a batch?

Use the PMF of the binomial distribution with n=10, p=0.2, and k=3

Use the PDF of the normal distribution with mean 2 and standard deviation 1.26

Multiply n by p to get the expected value and use that as the probability

Use the CDF of the binomial distribution with n=10, p=0.2, and k=3

CompTIADataX

Domain 1Objective 2

Probability and Modeling DY0-001 Practice Questions (Page 3)

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 11–15

11application · medium
A data scientist is modeling the time between customer service requests at a call center. The requests arrive independently, and the scientist needs to calculate the probability that the next request arrives within the next 3 minutes. The scientist has already fitted a continuous probability distribution to the inter-arrival times. Which function should the scientist use directly to answer this question?
Select an answer first
12foundation · easy
What is stratification in the context of statistical sampling?
Select an answer first
13foundation · easy
What does kurtosis measure in a probability distribution?
Select an answer first
14foundation · easy
What does the probability mass function (PMF) provide for a discrete random variable?
Select an answer first
15application · medium
A data analyst is modeling the number of defects per batch of products. The analyst finds that the number of defects follows a binomial distribution with n=10 trials and p=0.2. What is the probability of observing exactly 3 defects in a batch?
Select an answer first

Finished these 5 questions?

Review the revealed explanations, or continue through the curriculum.

Next 5 questions →Back to DY0-001

Free Basic Practice is a study aid with revealable answers — not a scored exam. Examers.io is independent and not affiliated with or endorsed by CompTIA. “DY0-001” is a trademark of its owner, used for identification only.