Means
What is the purpose of the critical value in a two-sample t-test?
To compare with the test statistic to make a decision
To determine the sample means
To calculate the p-value
To calculate the degrees of freedom
When conducting a hypothesis test for two independent means with unknown population standard deviations, what kind of distribution is typically used?
Binomial distribution
Chi-squared distribution
T-distribution
Normal distribution
When comparing the means of two independent samples, which graphical display would best identify potential outliers in both data sets?
Bar graphs
Pie charts
Histograms
Boxplots
What statistical test should be used to determine if there is a significant difference between two independent samples with unequal variances?
Paired t-test
Chi-square test for independence
Equal-variance t-test (Student's t-test)
Welch’s t-test
Which technique ensures control over familywise error rate when conducting multiple comparisons after ANOVA indicates at least one mean differs?
Bonferroni correction by adjusting alpha level divided by the number of tests.
Post-hoc Tukey’s HSD test without adjusting overall alpha level.
Paired t-tests between each group mean without alpha adjustment.
Repeated measures analysis without considering individual comparisons.
In the context of testing differences between groups, what does a Type I error represent?
Accepting a false null hypothesis
Failing to reject a true alternative hypothesis
Rejecting a true null hypothesis
Accepting a false alternative hypothesis
Which factor could potentially invalidate conclusions drawn from a t-test for the difference in population means?
A difference in sample means that appears to be statistically significant.
Failure to control confounding variables in two groups being compared.
A smaller than usual effect size in the populations being studied.
Utilization of technology to run the test instead of manual calculations.

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In a study to compare the mean reading speeds of two different populations, high school students and college students, which assumption is necessary for the t-test for the difference between two means to be valid?
The data collected must come from a census of both populations.
The samples from both populations are independent random samples.
The sample size for both populations must be over 30.
Both populations have the same standard deviation.
In a study that aims to compare the average effects of two drugs on heart rate in patients, what condition increases the likelihood of a Type II error occurring during this analysis?
More stringent significance criteria, such as lower alpha levels, thereby increasing the threshold of evidentiary support required before rejecting the null premise in favor of the alternative position.
Larger numbers of participating individuals, hence minimizing the potential for making a type II mistake as it occurs less often in larger groups.
Reduced effect size of medications, lowering the chances of detecting a true difference if it exists.
Increased variability within subject responses, which will eventually cancel out across the entire group, leaving a more pronounced overall trend visible despite increased spread of individual reactions.
How does having unequal variances in samples from two populations affect conducting a t-test for their mean differences?
It invalidates any form of t-tests requiring equal treatment on both variances.
It allows applying pooled variance estimates enhancing test precision significantly.
It solely affects calculation of margin of error but not overall feasibility or outcome of t-test.
It necessitates using modified degrees of freedom that may lead to a more conservative t-test result.