BIOL 3327 Experimental Methods Lecture 8 Review

A collection of flashcards to review key concepts from BIOL 3327 Lecture 8, focusing on statistical methods and the t-test.

What are the key statistics that characterize a population in BIOL 3327?

Mean and standard deviation.

What is the purpose of a t-test in statistics?

To determine if the difference between two means is significant in relation to the variation in the data.

What is the significance level commonly used in t-tests?

P ≤ 0.05, representing a 1 in 20 chance of a false positive.

How does the t-distribution behave with smaller sample sizes?

It becomes broader and flatter, widening the confidence limits.

What does s.e.d.m. stand for?

Standard error of differences between means.

What does a small sample size imply about the estimate of variance?

A worse estimate of variance due to increased uncertainty.

How many degrees of freedom are typically assigned in t-tests for n samples?

Degrees of freedom = n - 1.

What must be considered when conducting a t-test regarding the variance between populations?

The t-test can account for differences in variance, impacting the degrees of freedom.

What is the difference between a paired t-test and an unpaired t-test?

A paired t-test compares means from the same individual or matched pairs, while an unpaired t-test compares means from two independent groups.

What happens to the t-test cut-off value as sample size increases?

It may approach the normal distribution cut-off value of 1.96 for large samples.

What is the pooled variance in the context of a t-test?

It is the combined estimate of variance from both groups being compared.

In a t-test, what is the null hypothesis typically asserting?

The null hypothesis typically asserts that there is no difference between the population means.

Why is it essential to account for sample size when performing a t-test?

To accurately estimate variance and determine the validity of the test results.

What adjustment is necessary when sample sizes differ between two groups in a t-test?

Use the pooled standard error to account for differences in sample sizes.