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The Normal probability distribution is defined by two parameters: its mean and standard deviation (sd) and, between them, these two can define infinitely many different Normal distributions. The Normal distribution is very common but there is no simple way to use it to calculate probabilities.

However, the probabilities for the Standard Normal distribution (mean = 0, sd = 1) have been calculated numerically and are tabulated for quick reference.

The z-score is a linear transformation of a Normal variable and it allows any Normal distribution to be converted to the Standard Normal. Finding the relevant probabilities is then a simple task.

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โˆ™ 2014-05-15 14:16:07
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Q: What is a z score and what its used for?
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Related questions

What is the difference between Z-Test and The Z-score?

The Z-score is just the score. The Z-test uses the Z-score to compare to the critical value. That is then used to establish if the null hypothesis is refused.

What is z score of area 0.75?

what is the z score for 0.75

Can z score be possible 5?

Yes a Z score can be 5.

Calculate the z-score for a test score of 87 if the mean test score is 81.1 and standrd deviation is 11.06?

z score = (test score - mean score)/SD z score = (87-81.1)/11.06z score = 5.9/11.06z score = .533You can use a z-score chart to calculate the probability from there.

What does it mean if the Z score of a test is equal to 0?

If the Z Score of a test is equal to zero then the raw score of the test is equal to the mean. Z Score = (Raw Score - Mean Score) / Standard Deviation

How do you prove a z-score?

A z-score is a linear transformation. There is nothing to "prove".

What is the z score that correspond to P18?

Find the Z score that correspond to P25

Can a negative z score be greater than a positive z score?

Assume the z-score is relative to zero score. In simple terms, assume that we have 0 < z < z0, where z0 is the arbitrary value. Then, a negative z-score can be greater than a positive z-score (yes). How? Determine the probability of P(-2 < z < 0) and P(0 < z < 1). Then, by checking the z-value table, you should get: P(-2 < z < 0) ≈ 0.47725 P(0 < z < 1) ≈ 0.341345

What is the z-score for 1.87?

The z-score must be 1.87: the probability cannot have that value!

What is the value of a 'z' score of 0?

A z-score of 0 means the value is the mean.

What is true if someone has a z score of zero?

Z score of 0 is the mean of the distribution.

How do you find probabilty of negative z score?

Let z be positive so that -z is the negative z score for which you want the probability. Pr(Z < -z) = Pr(Z > z) = 1 - Pr(Z < z).

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