#1
Which of the following best describes statistical inference?
Drawing conclusions about a population based on a sample
ExplanationStatistical inference involves making predictions or decisions about a population based on a limited sample of data.
#2
What is the purpose of randomization in experimental design?
To eliminate bias and control for confounding variables
ExplanationRandomization ensures that each experimental condition has an equal chance of being assigned, minimizing bias and confounding variables.
#3
Which of the following is NOT an assumption of linear regression?
Multicollinearity
ExplanationMulticollinearity is not an assumption but rather a potential issue in linear regression, affecting the stability of coefficient estimates.
#4
What is the purpose of a control group in an experiment?
To provide a baseline for comparison with the treatment group
ExplanationA control group serves as a baseline to assess the impact of the treatment by providing a reference for comparison.
#5
Which statistical test is used to compare means of two independent groups?
Independent samples t-test
ExplanationThe independent samples t-test assesses whether the means of two independent groups are significantly different from each other.
#6
What is a Type II error?
Failing to reject the null hypothesis when it is false
ExplanationA Type II error occurs when the null hypothesis is false, but the test fails to reject it, leading to a missed detection of a true effect.
#7
In hypothesis testing, what does the p-value represent?
The probability of observing the data given that the null hypothesis is true
ExplanationThe p-value quantifies the evidence against the null hypothesis, indicating the probability of obtaining the observed data if the null hypothesis is true.
#8
What is the purpose of a power analysis in experimental design?
To determine the sample size needed to detect a specified effect size with a desired level of power
ExplanationPower analysis helps in determining the required sample size to achieve sufficient statistical power to detect a meaningful effect.
#9
What is the central limit theorem?
It describes the behavior of a sample mean as the sample size increases
ExplanationThe central limit theorem states that, as the sample size increases, the distribution of the sample mean approaches a normal distribution.
#10
What is the purpose of a factorial design in experiments?
To test the effects of multiple independent variables simultaneously
ExplanationFactorial design allows researchers to investigate the impact of multiple independent variables on the dependent variable in a single study.
#11
What is the purpose of a crossover study design?
To compare the effects of two or more treatments over time within the same group of participants
ExplanationCrossover design involves exposing each participant to multiple treatments in a random order, allowing within-subject comparisons.
#12
What is the purpose of an interaction term in regression analysis?
To test whether the relationship between two variables depends on the value of a third variable
ExplanationInteraction terms in regression help assess whether the relationship between two variables varies based on the levels of a third variable.