Galaxy Clusters Have Been Observed to Be Rich in Hot,X-Ray-Emitting

question 27

Multiple Choice

Galaxy clusters have been observed to be rich in hot,X-ray-emitting gas.What is keeping the gas in the cluster?

• A) dark matter
• B) the gravitational pull of the galaxies
• C) the electromagnetic radiation emitted by the galaxies
• D) the low speed of the hot gas

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Definitions:

Matched-Pairs Sampling

A sampling technique where each member of one sample is paired with a member of another sample based on certain characteristics.

Wilcoxon Signed Rank

A non-parametric statistical test used to compare two paired samples, assessing whether their population mean ranks differ.

Paired Two-sample T-test

A statistical test used to compare two population means where you have two samples in which observations in one sample can be paired with observations in the other sample.

Wilcoxon Signed Rank

The Wilcoxon Signed Rank Test is a non-parametric statistical test used to compare two related samples, matched samples, or repeated measurements on a single sample to assess differences in their population mean ranks.