Sigma and the probability of events?

a "sigma event" is an event that takes place when the observation is at least 3 standard deviations away from the mean.

P( Z < -3) + P(Z > 3)

= 0.001349898 + 0.001349898

= 0.002699796

for a 4 sigma event we have:

2 * P(Z < - 4) = 6.334248e-05

5 sigma

2 * P(Z < -5) = 5.733031e-07

6 sigma

2 * P(Z < -6) = 1.973175e-09

3 Sigma Probability

So being that this is your senior year, you are already lacking on many of the essential criteria Delta Sigma Theta is looking for. By this point in college you should have a sufficient amount of community service, strong leadership roles through out the school, at least know a couple of members, attended numerous events of theirs, and done all the history research for their chapter and sorority. If you feel strongly about DST, and you feel that your heart and your mind is dedicated to making this sorority better, I would put in for membership. Though your resume is lacking, they may give you a chance. The chance is small though. I would try to get to know them as much as possible in the next couple of months, and attend EVERY event, community service, anything that they are at starting now. I just want you to know, that your GPA is not where you want it to be right now, and it is known that pledging usually affects the GPA in a negative way. It's your decision if you want to risk your GPA standing for pledging. Now there are other opportunities that are available if you decided not to apply for memberships during your undergrad years. They have graduate chapters, therefore you can become a Delta Sigma Theta in graduate school. Again, what you failed to do in undergrad, you must excel in graduate because membership at this level is by invitation only. Attend all events, know who and where the graduate chapter is. Stay focused, and strong! Good luck!

3 sigma event? 0.5782%

4 sigma event? 0.0165%

5 sigma event? 0.0002%

"calculate" by "look-up" table.