Describe Two Time-Related Threats to Internal Validity

question 61

Essay

Describe two time-related threats to internal validity.(Note: For each threat,be sure to label it,describe it,and be sure to indicate how it specifically is a threat to the internal validity of the design.)

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Definitions:

Efferent Neurons

Neurons that transmit action potentials from the brain or spinal cord to muscles or glands. Compare with afferent neurons.

Sonar

Sonar is a technique that uses sound propagation (usually underwater) to navigate, communicate, or detect other vessels by sending out pulses of sound and listening for echoes.

Echolocation

Determination of the position of objects by detecting echoes of high-pitched sounds emitted by an animal; a type of sensory system used by bats and dolphins.

Thermoreceptors

Sensory cells or nerve endings specialized in detecting variations in temperature, found in the skin and other parts of the body.