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Calculate the Z value and determine the area (probability) between the Z values. Z = (x-mu)/sigma. Z42 = (42-50)/4 = -2 & Z68 = (68-50)/4 = 4.5. Go to the related link and the areas are .0228 & for 4.5 use .9999. Subtract the two values; .9999 - .0228 = .9771.

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If normal distribution is between 110 and 190 how can I find the probability that it will be between 135 and 165?

You need to know the standard deviation or standard error to answer the question.


Difference between standard deviation and mean devition?

The mean deviation (also called the mean absolute deviation) is the mean of the absolute deviations of a set of data about the data's mean. The standard deviation sigma of a probability distribution is defined as the square root of the variance sigma^2,


What is the relationship between standard deviation and accuracy?

It depends what you're asking. The question is extremely unclear. Accuracy of what exactly? Even in the realm of statistics an entire book could be written to address such an ambiguous question (to answer a myriad of possible questions). If you simply are asking what the relationship between the probability that something will occur given the know distribution of outcomes (such as a normal distribution), the mean of that that distribution, and the the standard deviation, then the standard deviation as a represents the spread of the curve of probability. This means that if you had a cure where 0 was the mean, and 3 was the standard deviation, the likelihood of observing a value of 12 (or -12) would be likely inaccurate if that was your prediction. However, if you had a mean of 0 and a standard deviation of 100, the likelihood of observing of a 12 (or -12) would be quite likely. This is simply because the standard deviation provides a simple representation of the horizontal spread of probability on the x-axis.


What is the difference between a general normal curve and a standard normal curve?

A standard normal distribution has a mean of zero and a standard deviation of 1. A normal distribution can have any real number as a mean and the standard deviation must be greater than zero.


Distinguish between mean deviation and standard deviation?

The mean deviation for any distribution is always 0 and so conveys no information whatsoever. The standard deviation is the square root of the variance. The variance of a set of values is the sum of the probability of each value multiplied by the square of its difference from the mean for the set. A simpler way to calculate the variance is Expected value of squares - Square of Expected value.


Percentage between 415 and 515 standard deviation 100 and mean is 515?

34.1% with the normal distribution.


What is the difference between t-distribution and standard normal distribution?

the t distributions take into account the variability of the sample standard deviations. I think that it is now common to use the t distribution when the population standard deviation is unknown, regardless of the sample size.


Does standard deviation have to be between 0 and 1?

Standard deviation doesn't have to be between 0 and 1.


What is the relationship between standard deviation and variance?

Standard deviation is the square root of the variance.


The probability density function has what value in the interval between 20 and 28?

I think you left off some important information. Perhaps you can supply this information, to obtain assistance. To calculate the probability or the chance of occurrence between two values, we calculate: Pr{a < X < b} = F(b) - F(a) where F(x) = cumulative probability distribution. The distribution requires certain known parameters. In the case of the Normal distribution, the mean and standard deviation are parameters. In your particular case, a = 20 and b = 28.


Relation between mean and standard deviation?

Standard deviation is the variance from the mean of the data.


What proportion are between 20 and 40 days old if there is Normal distribution with a mean of 28days and standard deviation of 8 days?

77.45%