Why Is It Necessary to Use the Pooled Variance When

question 5

Multiple Choice

Why is it necessary to use the pooled variance when conducting an independent-samples t test?

• A) We are working with two samples, and an estimate of spread based on two samples is likely to be more accurate than an estimate of spread based on a single sample.
• B) It is necessary to estimate the standard deviation of the two samples in order to compare the two samples to one another.
• C) Estimating the spread of the sample using the standard deviation increases the generalizability of results.
• D) Using the pooled variance helps the researcher identify skewness.

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Definitions:

Spearman's Rank-Correlation

A nonparametric measure of rank correlation that assesses the strength and direction of association between two ranked variables.

Correlation Coefficient

A measure that determines the degree to which two variables' movements are associated, ranging from -1 to 1.

Friedman Test

A non-parametric test used to detect differences in treatments across multiple test attempts.

Randomized Block Experiment

An experimental design that groups subjects into blocks based on certain intrinsic characteristics before randomly assigning treatments within each block to account for variability.