Answer:
0.1151 = 11.51% probability of completing the project over 20 days.
Step-by-step explanation:
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Expected completion time of the project = 22 days.
Variance of project completion time = 2.77
This means that
What is the probability of completing the project over 20 days?
This is the p-value of Z when X = 20, so:
has a p-value of 0.1151.
0.1151 = 11.51% probability of completing the project over 20 days.