Of all customers purchasing automatic garage-door openers, 75% purchase a chain-driven model. Let X = the number among the next 15 purchasers who select the chain-driven model. a.? ?What is the pmf of X? b.? ?Compute P(X > 10). c.? ?Compute P(6 ? X ? 10). d.? ?Compute ? and ?2. e. ?If the store currently has in stock 10 chain-driven models and 8 shaft-driven models, what is the probability that the requests of these 15 customers can all be met from existing stock?
Motor Development TRADITIONAL VIEW Definition: “motor milestones”— wiring for these motor control behaviors are built into the systems and motor development occurs as the system matures (reaching region of brain matures so infant can reach) This gives a rigid sequence of development that leads to motor control and behavior. Emphasis: stability in timing and sequence Explanation: people have the same genetic blueprint and motor skills develop as voluntary movement venters of the brain “mature” and build upon reflexes Brain maturity determines when changes occur, therefore the mechanism is simple genetic occurrences. Problems: hard to go from genes to behaviors without middle steps, many brain structures are involved in complex tasks so it’s hard to say what part of the brain ‘mature