Roughly What Percentage of the Total Mass of a Galaxy

question 3

Multiple Choice

Roughly what percentage of the total mass of a galaxy is made up of luminous,or normal,matter?

• A) 5 percent
• B) 25 percent
• C) 50 percent
• D) 90 percent

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Definitions:

Mean

The arithmetic average of a set of numbers, calculated by adding up all the values and dividing by the count of numbers.

Variance

A statistical measure that determines the spread of numbers in a data set by calculating the mean of the squared differences from the mean.

Standard Normal

A normal distribution with a mean of zero and a standard deviation of one, commonly used in statistical analysis.

P(Z < 2)

The probability that a value Z, on a standard normal distribution, is less than 2.