Table of Contents
- 1 Why is normal distribution mean 0?
- 2 What is the probability of an exact value in normal distribution?
- 3 Why is it wrong to say that normal distributions have a mean of 0 and a standard deviation of 1?
- 4 Why is there a need to study normal distribution?
- 5 What makes the normal distribution a probability distribution?
- 6 Why the standard normal random variable is widely used for computations involving normal distributions?
- 7 What is the difference between probability density and normal distribution?
- 8 What is the probability that the random variable will take one deviation?
Why is normal distribution mean 0?
When we convert our data into z scores, the mean will always end up being zero (it is, after all, zero steps away from itself) and the standard deviation will always be one. Data expressed in terms of z scores are known as the standard normal distribution, shown below in all of its glory.
What is the probability of an exact value in normal distribution?
Note that with the normal distribution the probability of having any exact value is 0 because there is no area at an exact BMI value, so in this case, the probability that his BMI = 29 is 0, but the probability that his BMI is <29 or the probability that his BMI is < 29 is 50\%.
Why is the probability of a continuous variable 0?
The probability of a specific value of a continuous random variable will be zero because the area under a point is zero.
What is the probability that a standard normal random variable takes the value 0?
Any more standard deviations than that, and we generally say the probability is approximately zero. In this case, we would say the probability of being lower than 5.2 standard deviations below the mean is approximately zero: P(Z < -5.2) = 0 (approx.)
Why is it wrong to say that normal distributions have a mean of 0 and a standard deviation of 1?
The mean of 0 and standard deviation of 1 usually applies to the standard normal distribution, often called the bell curve. The most likely value is the mean and it falls off as you get farther away. If you have a truly flat distribution then there is no value more likely than another.
Why is there a need to study normal distribution?
It is the most important probability distribution in statistics because it fits many natural phenomena. For example, heights, blood pressure, measurement error, and IQ scores follow the normal distribution.
What determines exact shape of a normal distribution?
What determines the exact shape of a Normal distribution? What are the values of the mean and the standard deviation for the standard Normal model? The shape depends on both the number of trials, n, and the probability of success, p.
Can the probability of a random variable be 0?
With continuous random variables (or more generally, an infinite number of possible outcomes) that intuition is flawed. Probability measure zero events can happen.
What makes the normal distribution a probability distribution?
Normal distribution, also known as the Gaussian distribution, is a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean. In graph form, normal distribution will appear as a bell curve.
Why the standard normal random variable is widely used for computations involving normal distributions?
The normal distribution is the most widely known and used of all distributions. Because the normal distribution approximates many natural phenomena so well, it has developed into a standard of reference for many probability problems. distributions, since µ and σ determine the shape of the distribution.
What is the probability of an exact value in a distribution?
For any continuous probability density distribution (normal or otherwise) the probability of a variable to be an exact value is zero. The reason is that’s a probability density distribution, not a probability distribution. When the difference between a and b is infinitisimally small, you can say that the probability to be at x is f ( x) d x.
Does the probability of any constant in the normal distribution equal zero?
I noticed that in the Normal distribution, the probability P ( x = c) equals zero, while for the Poisson distribution, it will not equal zero when c is a non-negative integer. My question is: Does the probability of any constant in the normal distribution equal zero because it represents the area under any curve?
What is the difference between probability density and normal distribution?
The probability density function is essentially the probability of continuous random variable taking a value. Normal distribution is a bell-shaped curve where mean=mode=median.
What is the probability that the random variable will take one deviation?
Using a table of values for the standard normal distribution, we find that P(–1 < Z ≤ 1) = 2 (0.8413) – 1 = 0.6826 Thus, there is a 0.6826 probability that the random variable will take on a value within one standard deviation of the mean in a random experiment.