The reaction time (in seconds) to a certain stimulus is a continuous random variable with pdf f(x) 3 2 x 1 2 1 x 3 0 otherwise a. Obtain the cdf. b. What is the probability that reaction time is at most 2.5 sec? Between 1.5 and 2.5 sec? c. Compute the expected reaction time. d. Compute the standard deviation of reaction time. e. If an individual takes more than 1.5 sec to react, a light comes on and stays on either until one further second has elapsed or until the person reacts (whichever happens first). Determine the expected amount of time that the light remains lit. [Hint: Let h(X) the time that the light is on as a function of reaction time X.]

Chapter 5: Short Term Working Memory Working Memory I. Short term memory can usually hold about 7 +/- 2 items A. Broken into chunks of information (ex: phone numbers are 7 digits and chunked) 1. Recoding: reduces the number of units held in STM by increasing the richness of each unit B. Cowan said 4 +/- 1 II. Forgetting in short term memory A. Decay: forgetting over time 1. Brown-Peterson Task B. Interference: there is a distraction (Peterson and Peterson) 1. Proactive: older material interferes with the current stimulus a) Release from PI: the decline in performance is reversed because if a change in the