Independent Samples t Tests

Flashcards summarizing key concepts from Independent Samples t Tests lecture notes focusing on the statistical test process and underlying principles.

What is an Independent Samples t Test?

A statistical test used to compare two samples from different individuals to each other.

What is the main focus of an Independent Samples t Test?

To compare the means of two groups rather than individual observations.

What is required to create a distribution of differences between means?

A comparison distribution that assumes the differences between groups could be random.

How do you calculate the mean of Group 1 in an Independent Samples t Test?

Randomly select three cards and calculate their mean.

What hypothesis is tested in an Independent-Samples t Test?

Null hypothesis states there is no difference between the means; alternative hypothesis states there is a difference.

What does the null hypothesis (H0: μ1 = μ2) imply in an Independent Samples t Test?

It implies that average ratings are the same for both groups.

How is the variance for each group calculated in an Independent Samples t Test?

By using the sum of squared differences from the mean divided by the degrees of freedom.

What does pooled variance account for in an Independent Samples t Test?

It provides a weighted average of the two sample variances to reduce estimation error.

What is the critical value used for significance testing in an Independent Samples t Test?

Values that help determine if the null hypothesis can be rejected, often set at α = 0.05.

What does it mean if the confidence interval does not contain zero?

It indicates a significant difference exists between the means of the two groups.

What is Cohen’s d in the context of an Independent Samples t Test?

A measure of effect size that indicates the standard deviations difference between the two sample means.

What can affect the standard error in an Independent Samples t Test?

The size and variance of the samples from which the means are calculated.

When are independent-samples t tests appropriate to use?

When comparing means from two different groups or populations.

What statistical significance level is commonly used in hypothesis testing for t-tests?

An alpha level of 0.05.

How do you report results in an Independent Samples t Test?

Using the format t(df) = tcalc, p < 0.05 for significant results.

What is the significance of degrees of freedom in pooled variance calculation?

Degrees of freedom reflect the sample sizes and affect the weight of each sample's variance.

Why is it important to use the pooled standard deviation in calculating effect size?

It provides a more accurate measure for comparing effect sizes between two groups.