please help have gotten it wrong multiple

Variability in Individual Activities 0 PERT accounts for uncertainty in activity times 0 Uses 3 time estimates for each activity 0 Optimistic time (a) 0 Pessimistic time (b) 0 Most likely time (m) 0 Calculations based on the Beta distribution 0 Expected activity time t = (a + 4m + b)/6 0 Variance = [(b a)/6]/\\2 0 Standard deviation = SQRT(variance) = (b a)/6 Probabili Densityty O 1 2 3 4 5 6 Time Required Beta Distribution Value: 3 For an activity, optimistic time (a) is 1, most likely time (m) is 4, and pessimistic time (b) is 7. Then, expected time will be 3.166 standard deviation will be 0.25 and variance will be Check Answer 0.5 Sorry, incorrect answer. Points scored this item: 0 Project Variance and Standard Deviation