How does Apache JMeter handle distributed testing across multiple machines?
- By configuring multiple virtual hosts
- By deploying multiple instances on a single machine
- By dividing test cases among team members
- By using master-slave architecture
Apache JMeter handles distributed testing through a master-slave architecture. The master orchestrates the test execution by distributing the load among slave machines. This approach allows for scalability and the simulation of real-world scenarios with a higher number of concurrent users. It enables efficient utilization of resources and better performance testing of applications under different conditions.
Which of the following best describes a key principle of Continuous Integration (CI)?
- Frequent and automated code integration
- Isolating developers from the integration process
- Manual testing before code integration
- Performing integration only at the end
A key principle of Continuous Integration (CI) is frequent and automated code integration. In CI, developers regularly integrate their code changes into a shared repository. Automated build and test processes are triggered upon each integration, helping to identify integration issues early in the development cycle. This practice ensures that the software remains in a continuously integratable state, leading to faster feedback and improved collaboration among team members.
The Sign Test is based on the direction of the _________ between pairs.
- differences
- medians
- ranks
- signs
The Sign Test is based on the direction of the differences between pairs.
How does the Law of Large Numbers impact the calculation of probabilities?
- It changes the probability of an event based on previous outcomes.
- It doesn't affect the calculation of probabilities.
- It guarantees that the experimental probability gets closer to the theoretical probability as the number of trials increases.
- It states that all probabilities must be equal.
The Law of Large Numbers impacts the calculation of probabilities by asserting that as the number of trials (or observations) increases, the experimental probabilities will get closer and closer to the theoretical (or true) probabilities. It gives validity to the notion of probability in practical applications.
If two events A and B are mutually exclusive, the probability of both occurring is _______.
- 0
- 0.5
- 1
- The probability is undefined
If two events A and B are mutually exclusive, the probability of both occurring is 0. Mutually exclusive events cannot occur at the same time.
How does the sample size relate to the power of a test?
- It depends on the effect size
- Larger sample sizes decrease power
- Larger sample sizes increase power
- Sample size has no influence on power
Larger sample sizes increase the power of a test because they provide more data, reducing the influence of random error and making it easier to detect an effect if one exists. This is why researchers often aim to recruit as large a sample as possible, within the constraints of their resources.
In multiple linear regression, the __________ test is used to test if a group of variables contributes to the prediction of the response.
- Chi-square test
- F-test
- T-test
- Z-test
The F-test is used in multiple regression to test whether at least one of the predictors' regression coefficient is not equal to zero. In other words, it tests whether the predictors are significant in explaining the response variable.
How does a higher R-squared value impact the inference in multiple linear regression?
- It decreases the number of observations
- It improves the interpretability of the model
- It increases the residuals
- It makes the model more complex
The R-squared value measures the proportion of the variance in the dependent variable that is predictable from the independent variables. A higher R-squared value, closer to 1, implies a higher proportion of variability in the response variable is explained by the predictors, improving the model's interpretability and predictive power.
The _______ test compares the means of two independent groups.
- Chi-square
- Independent t
- Paired t
- Z
An Independent t-test (or two sample t-test) compares the means of two independent groups.
The optimal number of clusters in K-means clustering is often determined using the ________ method.
- elbow
- foot
- hand
- knee
The optimal number of clusters in K-means clustering is often determined using the elbow method. This involves plotting the explained variation as a function of the number of clusters and picking the elbow of the curve as the number of clusters to use.
What is the probability of an event that is certain to happen?
- 0
- 0.5
- 1
- The probability is undefined for certain events
The probability of an event that is certain to happen is 1. This is based on the definition of probability as a measure that takes values between 0 and 1, inclusive. An event with a probability of 1 is a sure event.
What techniques can be used to detect multicollinearity in a multiple regression model?
- Analysis of Variance (ANOVA)
- Chi-square test
- T-test
- Variance Inflation Factor (VIF)
The Variance Inflation Factor (VIF) is commonly used to detect multicollinearity in regression analysis.