Collecting Data
How does reliance solely on randomization as an inferential procedure impact the ability to detect the actual causality underlying an observed association?
It limits inferential capability to confirm causality despite establishing temporal precedence and controlling for confounding variables
It enhances causative determinations by exclusively attributing variations to the treatment effect and inherent randomness in the process
It precludes the necessity of considering external causal factors given the sufficiency of internal validity provided by random assignment alone
It ensures the complete removal of subjectivity in decision-making, leading to pristine, objectified conclusions regarding cause-effect relationships
A researcher conducts a simulation to check the robustness of a t-test assumption of normality in a violated scenario. What should they expect to see regarding the accuracy of p-values generated?
Larger p-value inaccuracies are detected as larger deviations from the normal distribution occur in insignificant ways.
P-value discrepancies are irrelevant as long as non-normal distributions sampled resemble a bell-shaped curve closely enough to pass muster.
Smaller p-value inaccuracies are detected as smaller deviations from the normal distribution occur in significant ways.
No discernible pattern emerges in terms of accuracy, as measured through the prism of deviation from the norms set forth at the beginning phase of experimental manipulation.
Which of the following best describes the purpose of a confidence interval in statistical inference?
To estimate the range within which a population parameter lies based on sample data.
To calculate the exact value of a population parameter from sample data.
To prove that one categorical variable has an effect on another.
To determine if there is a statistically significant difference between two sample means.
When comparing two means with an independent samples t-test, what assumption must be satisfied regarding variances?
The total variance for all samples combined must equal twice that of each separate sample's variance.
Heterogeneity of variances, meaning both populations have different but known variances.
Variance equality within samples rather than across populations being compared.
Homogeneity of variances, meaning both populations have equal variances.
When evaluating the design of a randomized controlled experiment, which factor best ensures that the effect of treatments is not confounded by other variables?
Random assignment to treatment groups
Matching participants on specific characteristics
Conducting the experiment in a controlled environment
Using a large sample size for the experiment
When increasing the sample size in a hypothesis test, assuming all other factors remain constant, what is the effect on the margin of error and statistical power?
The margin of error decreases and the statistical power increases.
The margin of error increases and the statistical power decreases.
Both margin of error and statistical power decrease.
Both margin of error and statistical power increase.
Which type of non-probability sample relies on data collection from population members who are conveniently available?
Convenience sampling
Stratified random sampling
Simple random sampling
Cluster sampling

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What impact does using a larger significance level (α) in hypothesis testing have on type I error rate and width of corresponding confidence intervals?
Type I error rate increases while widths of corresponding intervals decrease.
Both Type I error rate and widths remain unchanged since α only affects p-values calculation.
Type I error rate decreases while widths of corresponding intervals increase.
Type I Error rate increases but has no effect on widths which are affected by other factors.
In evaluating prediction models using disparate datasets with binary outcomes, which measure would not directly reflect the accuracy rate?
P-value from chi-square test for independence between predictor and response variables
Sensitivity or true positive rate
Positive predictive value
Specificity or true negative rate
If a researcher wants to compare the means of two related groups using a paired t-test, which assumption must be checked regarding the differences in the pair's responses?
The differences should be approximately normally distributed.
The variances within each group should be similar.
There should be no outliers in either group.
The sample sizes for both groups must be equal.