An Elliptical Galaxy in Boötes (Shown at the Bottom of Figure

question 46

Multiple Choice

An elliptical galaxy in Boötes (shown at the bottom of Figure 17-32 in the text) is at a distance of 1.6 billion ly and has an apparent recession speed of 39,000 km/s. What upper limit does this imply to the age of the universe? (Be careful with units.)

• A) 0.47 billion years
• B) 12 million years
• C) 47 billion years
• D) 12 billion years

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Definitions:

DRO

Differential Reinforcement of Other behavior, a strategy in behavior modification where reinforcement is provided for any behavior that is not the unwanted behavior.

DRL

Differential Reinforcement of Low Rates, a behavior modification strategy aimed at reducing the frequency of undesired behaviors.

DRL-IRT Schedule

A DRL schedule in which the target behavior is reinforced following a specified interval of time since the previous episode. The interval is determined by calculating interresponse time (IRT). The interval length is gradually increased until the target behavior occurs only after longer periods of time have passed.

Differential Reinforcement

A behavior modification technique that reinforces desired behaviors while withholding reinforcement for undesired behaviors.