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? • (19 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. (6 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
What is the formula for calculating the z-score? ›
The formula for calculating a z-score is z = (x-μ)/σ, where x is the raw score, μ is the population mean, and σ is the population standard deviation.
How do you calculate the z-score in AP stats? ›To calculate a z-score, we simply subtract the mean from a raw score and then divide by the standard deviation. (On exam questions, the mean and standard deviation may be provided, or you may need to calculate them, so make sure you know how to do that!)
How to calculate z-score calculator? ›- Calculate the mean as (∑x) / n .
- Calculate the standard deviation using the easy-to-type formula (∑(x²) - (∑x)²/n) / n . The divisor is modified to n - 1 for sample data.
- Calculate the z-score using the formula z = (x - mean) / standard deviation .
A z-score tells us the number of standard deviations a value is from the mean of a given distribution. negative z-scores indicate the value lies below the mean. positive z-scores indicate the value lies above the mean.
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 to find z-score with mean and percentile? ›1 Answer. Z = (x - mean)/standard deviation. Assuming that the underlying distribution is normal, we can construct a formula to calculate z-score from given percentile T%.
What is the formula for the z-score to P? ›The distribution for z is the standard normal distribution; it has a mean of 0 and a standard deviation of 1. For Ha: p ≠ 26, the P-value would be P(z ≤ -1.83) + P(z ≥ 1.83) = 2 * P(z ≤ -1.83). Regardless of Ha, z = (p̂ - p0) / sqrt(p0 * (1 - p0) / n), where z gives the number of standard deviations p̂ is from p0.
What is the z-score for 95 confidence interval? ›The Z value for 95% confidence is Z=1.96. [Note: Both the table of Z-scores and the table of t-scores can also be accessed from the "Other Resources" on the right side of the page.] What is the 90% confidence interval for BMI? (Note that Z=1.645 to reflect the 90% confidence level.)
What is the formula for z-score for a child? ›The formula for calculating the z-score according to the WHO is z-score = (X-m)/SD, in which X is the observed value (height, weight or BMI), m and SD are the mean and standard deviation value of the distribution corresponding the reference population.
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 formula? ›
Z Score = (x − x̅ )/σ
Where, x = Standardized random variable. x̅ = Mean. σ = Standard deviation.
A z score is unique to each value within a population. To find a z score, subtract the mean of a population from the particular value in question, then divide the result by the population's standard deviation.
What is the formula for the z-score of a sample size? ›| Formulas for Sample Size (SS) | |
|---|---|
| For Infinite Sample Size | SS = [Z2p (1 − p)]/ C2 |
| For Finite Sample Size | SS/ [1 + {(SS − 1)/Pop}] |
If x̅ is the sample mean, μ0 is the population mean, σ is the standard deviation, and n is the sample size, then the z-trial formula is expressed as follows: Z = (x̅ – μ0) / (σ /√n).