Suppose the Probability of X Occurring Is 1 in 4

question 3

Multiple Choice

Suppose the probability of X occurring is 1 in 4, and the probability of Y occurring is 1 in 5. What is the probability of both occurring?

• A) (1/4) + (1/5) = (5/20) + (4/20) = 9/20
• B) (1/4)² + (1/5)² = (1/16) + (1/25) = (25/400) + (16/400) = 41/400
• C) (1/4) × (1/5) = 1/20
• D) (1/4)² × (1/5)² = (1/16) × (1/25) = 1/400

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Definitions:

Human Vision

The ability of the eyes and brain to process light stimuli into images, enabling sight.

Candle Flame

The visible, luminous part of a candle that produces light and heat from the combustion of the candle’s fuel.

Absolute Threshold

The minimum intensity of a stimulus that one can detect 50% of the time.

Psychophysical Threshold

The minimum level of stimulus intensity needed for detection by sensory systems.