Proportions
What type of study design is most suitable for comparing two treatments to test for a difference in outcomes?
Controlled experiment
Case study research
Observational study without controls
Time series analysis
In hypothesis testing for two proportions, what does a larger standard error indicate about our point estimate?
We have eliminated nearly all sampling error from our estimates.
The two population proportions are probably identical.
The point estimate is likely very close to zero.
There's more variability in our estimate, and we're less certain about our true population parameter estimate.
Why must we check that individual observations within each group are independent when conducting a hypothesis test for two proportions?
To confirm that there is no significant interaction effect present.
It helps establish causation rather than just correlation.
Independence is required to apply nonparametric tests only.
To ensure accurate standard error estimation.
A presidential candidate wanted to know if support for her was significantly different between women and men. Her team randomly sampled 1000 voters of each gender and found that 756 of the 1000 women supported her and 560 of the 1000 men supported her. Are all three conditions of a two-proportion z-test satisfied?
Yes, all three conditions are satisfied
No, the normal condition is not satisfied
No, the independent condition is not satisfied
No, the random condition is not satisfied
A researcher conducts hypothesis tests comparing two population proportions using distinct methods resulting in different z-scores; if all else remains constant across methods except allocation ratios (sample sizes), what inference can we draw about these disparities in z-scores?
The calculated p-values will be nearly identical regardless of the difference in allocation ratios due to sampling variability...
The variance within each group was likely affected by differing allocation ratios contributing to dissimilarity in z-scores between methods...
Differential allocation ratios shouldn't affect results as long as total combined sample size is conserved across methods...
Differing z-scores suggest that one population proportion is much larger than the other rather than sample allocation effects...
In testing the difference between two population proportions, what is the first step you should always perform before proceeding with calculations?
Calculate the pooled sample proportion.
Perform a chi-square test for independence.
Determine the degrees of freedom.
Verify that the conditions for inference are met.
Suppose you conduct a significance test for the difference in two population proportions with the significance level set at 0.10. If the p-value is 0.17, what can you conclude?
There is not enough evidence to suggest that there is a statistically significant difference between the two population proportions.
There is not enough evidence to suggest that there is a statistically significant difference between the two sample proportions.
There is a statistically significant difference between the two population proportions.
There is a statistically significant difference between the two sample proportions.

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Which variability measure is used to determine the standard error for the difference between two sample proportions?
Range of sample data
Standard deviation of one population
Pooled sample proportion
Individual sample variance
In a study comparing two treatments with binary outcomes, how does increasing the sample size impact the width of a confidence interval for the difference in population proportions?
It decreases the width, making it more precise.
It has no effect on width but increases confidence level instead.
It increases the width due to higher variability with larger samples.
It decreases precision due to more data points deviating from mean differences.
Which method selects individual units in such a way that each unit in the population has an equal chance of being included in the sample?
Snowball sampling
Quota Sampling
Simple random sampling (SRS)
Convenience sampling