Log in 😊 8 years agoPosted 8 years ago. Direct link to 😊's post “how do I calculate the pr...” how do I calculate the probability of a z-score? • (20 votes) Piquan 8 years agoPosted 8 years ago. Direct link to Piquan's post “That's a great question! ...” That's a great question! Fortunately, the next set of lessons, at https://www.khanacademy.org/math/statistics-probability/modeling-distributions-of-data/normal-distributions-library/v/ck12-org-normal-distribution-problems-qualitative-sense-of-normal-distributions , discuss exactly that. It's great that you're thinking ahead! (27 votes) Nick Leshuk 8 years agoPosted 8 years ago. Direct link to Nick Leshuk's post “how do you calculate the ...” how do you calculate the mean when you are only given the z-scores? • (5 votes) RacheLee 8 years agoPosted 8 years ago. Direct link to RacheLee's post “To calculate the mean, yo...” To calculate the mean, you need to know z-scores, the data, and the standard deviation. (14 votes) Tou 6 years agoPosted 6 years ago. Direct link to Tou's post “how do you calculate this...” how do you calculate this: µ=10 and σ =1, P(X>10) • (6 votes) Shaghayegh 4 years agoPosted 4 years ago. Direct link to Shaghayegh's post “Is it necessary to assume...” Is it necessary to assume the distribution is normal? • (3 votes) loumast17 4 years agoPosted 4 years ago. Direct link to loumast17's post “to use z scores. If not,...” to use z scores. If not, or you do not know the population standard deviation you would use a different kind of score called the t score For z scoreyou need both the population standard deviation and for the sample to be greater than 30. There are other aspects in statistics where having a normal distribution is necessary. (7 votes) 1315031658 7 years agoPosted 7 years ago. Direct link to 1315031658's post “How do you find the data ...” How do you find the data when you have the mean, the z-score, and the standard deviation? • (2 votes) Ian Pulizzotto 7 years agoPosted 7 years ago. Direct link to Ian Pulizzotto's post “Let x represent the data ...” Let x represent the data value, mu represent the mean, sigma represent the standard deviation, and z represent the z-score. So the data value equals the z-score times the standard deviation, plus the mean. Have a blessed, wonderful day! (7 votes) sebastian grez 8 years agoPosted 8 years ago. Direct link to sebastian grez's post “what happens when you get...” what happens when you get the number of X-U/standar desviation ahd you get a number above 3, that number will not be in the tabla of Z • (4 votes) psthmn 7 years agoPosted 7 years ago. Direct link to psthmn's post “You could try to find a m...” You could try to find a more extensive Z table, for example here: http://www.intmath.com/counting-probability/z-table.php But at a certain point the difference in probality at changing z values gets vanishingly small, so it doesn't really matter what the actual value at that point is. If you are faced with this situation, in most cases P > P(Z=3) is a useful and sufficient answer. (1 vote) Bryan 4 years agoPosted 4 years ago. Direct link to Bryan's post “Are z-scores only applica...” Are z-scores only applicable for normal distributions? You could describe how many standard deviations far a data point is from the mean for any distribution right? But is the term z-score only for normal dists? • (3 votes) Rebecca 4 years agoPosted 4 years ago. Direct link to Rebecca's post “The z-score could be appl...” The z-score could be applied to any standard distribution or data set. It definition only depends on the (arithmetic) mean and standard deviation, and no other qualitative properties of the nature of the data set. (2 votes) Samael Pena 5 years agoPosted 5 years ago. Direct link to Samael Pena's post “What if I don't have the ...” What if I don't have the score but only the Z score. How can I calculate what the score is • (3 votes) muhammad fajar rizqi 7 years agoPosted 7 years ago. Direct link to muhammad fajar rizqi's post “Hello Everybody, I want t...” Hello Everybody, I want to ask, how to calculate that has z-score is more than 3 or -3? because sometimes i calculate the z-score and can't get the result because it's out of range from the z-table. Thank you • (3 votes) Rosivette Andrade 5 years agoPosted 5 years ago. Direct link to Rosivette Andrade's post “Would anyone mind explain...” Would anyone mind explaining this ? A. about 2 • (2 votes)Want to join the conversation?
z-score=(data-mean)/standard deviation
data-mean=(z-score)(standard deviation)
mean=(data)-(z-score)(standard deviation)
Since the z-score is the number of standard deviations above the mean, z = (x - mu)/sigma.
Solving for the data value, x, gives the formula x = z*sigma + mu.
For a normal distribution of 1000 cases, how many cases will be farther away from the mean than + 3 standard deviations?
B. at least 500
C. it is impossible to estimate
D. 327
FAQs
How do you find z-score formula? ›
Since the z-score is the number of standard deviations above the mean, z = (x - mu)/sigma. Solving for the data value, x, gives the formula x = z*sigma + mu.
How do you calculate the z-score quizlet? ›What is the formula for the z-score? z = x value - mean or mew/ divided by standard deviation or sigma.
What is the original z-score formula? ›The formula for Altman Z-Score is 1.2*(working capital / total assets) + 1.4*(retained earnings / total assets) + 3.3*(earnings before interest and tax / total assets) + 0.6*(market value of equity / total liabilities) + 1.0*(sales / total assets).
How is the z-score table calculated? ›Z-Score Formula
It is a way to compare the results from a test to a “normal” population. If X is a random variable from a normal distribution with mean (μ) and standard deviation (σ), its Z-score may be calculated by subtracting mean from X and dividing the whole by standard deviation.
- Calculate the mean of all the numbers x in vector X. Call the result m.
- Calculate the standard deviation of vector X, giving a single number s.
- Calculate the Z-score 'Z' as a new vector by subtracting x -m and divide the result by s.
Based on body mass Index (BMI)
Z-score and percentile equivalence: 3SD=0.1%; 2SD=2.3%; 1SD=15.9%; +1SD=84.1%; +2SD=97.7%; +3SD=99.9%.
z = (X – μ) / σ
where X is a normal random variable, μ is the mean of X, and σ is the standard deviation of X. You can also find the normal distribution formula here. In probability theory, the normal or Gaussian distribution is a very common continuous probability distribution.
To calculate a Z-score, you take the raw score x, subtract the mean, and divide by the standard deviation. This results in the transformed Z-score. The distribution of scores remains exactly the same. Essentially, the Z-score can be interpreted as the number of standard deviations that a raw score x lies from the mean.
How do you calculate the Z test? ›- Compute the arithmetic mean of your sample.
- From this mean subtract the mean postulated in null hypothesis.
- Multiply by the square root of size sample.
- Divide by the population standard deviation.
- That's it, you've just computed the Z test statistic!
Z Score = (x − x̅ )/σ
x = Standardized random variable. x̅ = Mean. σ = Standard deviation.
What is the easiest way to find the z-score? ›
If you know the mean and standard deviation, you can find the z-score using the formula z = (x - μ) / σ where x is your data point, μ is the mean, and σ is the standard deviation.
What is the sample size for the z-score? ›A z-test is used in hypothesis testing to evaluate whether a finding or association is statistically significant or not. In particular, it tests whether two means are the same (the null hypothesis). A z-test can only be used if the population standard deviation is known and the sample size is 30 data points or larger.
What is the z-score for 95 confidence interval? ›The value of z* for a specific confidence level is found using a table in the back of a statistics textbook. The value of z* for a confidence level of 95% is 1.96.
How do you calculate the financial z-score? ›The Z Score is calculated by multiplying several financial ratios by an appropriate coefficient and then summing the results. The ratios rely on the following financial measures. (Use balance sheet figures from the end of the reporting period for all Z Score calculations.)
What is the z-score for an IQ test score of 92 when the mean is 100 and the standard deviation is 15? ›Hence, for an IQ test score of 92 when the mean is 100 and the standard deviation is 15, the Z-score is -0.5333.
What is the z-score of 2? ›Z-scores can be positive or negative. The sign tells you whether the observation is above or below the mean. For example, a z-score of +2 indicates that the data point falls two standard deviations above the mean, while a -2 signifies it is two standard deviations below the mean. A z-score of zero equals the mean.