Why the value of Gaussian curve drop to 1/19 at 2 standard deviation?

1. What is the standard deviation of a Gaussian?
2. What are the two standard deviation in a normal curve?
3. What percentage of the area under the normal curve falls between 2 standard deviations?
4. How standard deviation affects normal curve?

What is the standard deviation of a Gaussian?

The nature of the gaussian gives a probability of 0.683 of being within one standard deviation of the mean. The mean value is a=np where n is the number of events and p the probability of any integer value of x (this expression carries over from the binomial distribution ).

What are the two standard deviation in a normal curve?

The normal distribution is the proper term for a probability bell curve. In a normal distribution the mean is zero and the standard deviation is 1.

What percentage of the area under the normal curve falls between 2 standard deviations?

Regardless of what a normal distribution looks like or how big or small the standard deviation is, approximately 68 percent of the observations (or 68 percent of the area under the curve) will always fall within two standard deviations (one above and one below) of the mean.

How standard deviation affects normal curve?

Know that increasing the standard deviation produces a flatter and wider bell-shaped curve and that decreasing the standard deviation produces a taller and narrower curve. Normal curves can be convenient summaries of data whose histograms are mound-shaped and roughly symmetric.