The Amount of Money That Maria Earns in a Week

question 84

Multiple Choice

The amount of money that Maria earns in a week is a random variable,X,with a mean of $900 and a standard deviation of
.The amount of money that Daniel earns in a week is a random variable,Y,with a mean of $800 and a standard deviation of
.The difference,X - Y,between Maria's weekly income and Daniel's weekly income is a random variable with a mean of $900 - $800 = $100.If the incomes are independent of one another,which of the following shows the correct method for calculating the standard deviation of the random variable X - Y?

• A)SD(X -
• Y)= Var(X -
• Y)= Var(
• X)+ Var(
• Y)= +
• B)SD(X -
• Y)= = =
• C)SD(X -
• Y)= SD(
• X)+ SD(
• Y)= +
• D)SD(X -
• Y)= SD(
• X)- SD(
• Y)= -
• E)SD(X -
• Y)= = =

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Definitions:

Incentive

A factor, often external, that motivates or encourages an individual to act in a certain way.

Goal Object

The target or endpoint of an individual's efforts or ambitions.

Partial Reinforcement

A conditioning schedule in which a reward is not provided every time the desired response is exhibited, making the response more resistant to extinction.

Continuous Reinforcement

A reinforcement schedule in which a reward follows every correct response, often used to teach new behaviors.