Exploring One–Variable Data
What is it called when you divide a population into groups and then choose a separate SRS from each group?
Stratified Sampling
Cluster Sampling
Multistage Sampling
Systematic Sampling
What type of study design reduces the impact of confounding variables most effectively when trying to determine if there is a causal relationship between two variables?
Matched pairs design in observational studies.
Randomized controlled experiments.
Stratified random sampling in observational studies.
Retrospective cohort studies using historical data.
Which measure is not affected by extreme values or outliers in a dataset?
Standard Deviation
Median
Mean
Range
Given a set of data with non-normal residuals, which technique could best transform the response variable to enable valid inferences using parametric methods?
Logarithmic Transformation
Adding Adjustment Constant To Each Score
Box-Cox Transformation Method
Multiplying Each Score By A Constant Factor
When constructing confidence interval estimates for proportions using binomial distribution, why might Bayesian estimate techniques be preferred over traditional frequentist methods?
They offer uniformly higher statistical power, especially when dealing with very large sample sizes.
They guarantee zero percent probability of type II error as long as the true proportion lies somewhere within the calculated range.
They provide wider confidence intervals that are tentatively conservative by default, resulting in lower risk of falsely claiming significance.
They allow incorporation of prior knowledge and beliefs regarding the parameter in question, thus providing a more tailored estimate given the context and specific situations.
When assessing whether class participation affects final grades, which type of study minimizes confounding variables?
Observational study comparing final grades of volunteers and non-volunteers in class participation
Randomized controlled experiment assigning some to participate and others not by random selection
Case study involving detailed records from several high-participation and low-participation classes
Survey asking students about their perceived impact of class participation on their grades
What type of statistical technique allows one to predict values of one variable based on known values of two or more variables while simultaneously assessing individual variable contributions?
Simple linear regression analysis
Multiple linear regression analysis
One-way Analysis Of Variance (ANOVA)
Pearson's correlation coefficient (r)

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Which statement correctly justifies why we use t-distributions instead of normal distributions when constructing confidence intervals for means?
The normal distribution requires that we know the exact standard deviation of the population, which is rarely known in practice.
The t-distribution has fatter tails than the normal distribution, accommodating more uncertainty when estimating from small samples.
T-distributions are used because they provide narrower intervals, leading to more precise estimates regardless of sample size.
Normal distributions can only be used with populations known to follow a uniform distribution, making them less versatile than t-distributions.
When conducting an experiment where subjects don't know if they're receiving a treatment or placebo but researchers do know who belongs to each group, this kind of experimental design is known as what?
DOUBLE-BLIND STUDY neither participant nor researcher aware assignments
BLOCK DESIGN carefully assigns treatments within defined blocks
BLIND STUDY where participants unaware their assignment
SINGLE-BLIND STUDY where only participant blinded information
What is the probability of flipping a fair coin and getting heads?
0.75
0.5
1
0.25