Log in 😊 7 years agoPosted 7 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 7 years agoPosted 7 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! (25 votes) Nick Leshuk 7 years agoPosted 7 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 7 years agoPosted 7 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 5 years agoPosted 5 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 3 years agoPosted 3 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 3 years agoPosted 3 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 6 years agoPosted 6 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 6 years agoPosted 6 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 7 years agoPosted 7 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 6 years agoPosted 6 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 4 years agoPosted 4 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 to calculate Z-scores (formula review) (article) | Khan Academy? ›
Let x represent the data value, mu represent the mean, sigma represent the standard deviation, and z represent the z-score. Since the z-score is the number of standard deviations above the mean, z = (x - mu)/sigma.
What is the formula for calculating the z-score? ›Z Score = (x − x̅ )/σ
Where, x = Standardized random variable. x̅ = Mean. σ = Standard deviation.
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 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 is a statistical measurement of a score's relationship to the mean in a group of scores. A Z-score can reveal to a trader if a value is typical for a specified data set or if it is atypical. In general, a Z-score of -3.0 to 3.0 suggests that a stock is trading within three standard deviations of its mean.
What is the original z-score formula? ›The original Z-score formula was as follows: Z = 1.2X1 + 1.4X2 + 3.3X3 + 0.6X4 + 1.0X5. X1 = ratio of working capital to total assets. Measures liquid assets in relation to the size of the company.
How to calculate the z test? ›The formula for calculating the Z Test statistic is Z = (x̄ - µ) / (σ / √n). Here x̄ is the sample mean, µ is the population mean, σ is the population standard deviation, and n represents the sample size.
How do you calculate grade with z-score? ›For example, suppose a student gets a 58 on exam 2, where the mean grade is 48.8 and the standard deviation is 18.5. Her z-score is (58-48.8)/18.5 = 0.497. This is equivalent to a grade of 81.5 on exam 1, where the mean grade was 74 and the standard deviation was 15.1.
What is the code to find the z-score? ›z = (X – μ) / σ
z = Z-Score. X = Value of Element. μ = Population Mean.
Z-score and percentile equivalence: 3SD=0.1%; 2SD=2.3%; 1SD=15.9%; +1SD=84.1%; +2SD=97.7%; +3SD=99.9%.
How do you calculate percentage from z-score? ›
Using the standard normal table (in your book or on our Course Site) we look up the area of the left tail associated with z-value of -1.33. We multiply this by 100 % to get a percent. Rounded to the nearest percent this is 9%.
How do you calculate critical z-score? ›Step 1: Determine the confidence level, denoted , where is a number (decimal) between 0 and 100. Step 2: Obtain the confidence level, denoted by evaluating α = 1 − C 100 . Step 3: Use the -table (or a calculator) to obtain the -score z α / 2 .
What is a good z-score value? ›0 is used as the mean and indicates average Z-scores. Any positive Z-score is a good, standard score. However, a larger Z-score of around 3 shows strong financial stability and would be considered above the standard score. A negative Z-score value is a bad sign.
What is the formula for z-score in Excel? ›The formula for computing a z-score is =(DataValue-Mean)/StDev. For example, to compute a z- score for the first value in our data set, we use the formula =(A2-$D$2)/$E$2 as Figure 1 illustrates. Notice the dollar signs $ in the formula. These dollar signs are what are known as absolute markers.
What does the z-score chart tell you? ›A z-table shows the percentage or probability of values that fall below a given z-score in a standard normal distribution. A z-score shows how many standard deviations a certain value is from the mean in a distribution.
What is the calculated z value? ›To calculate the standard error of the mean, you can use the following formula:Z = (x - μ) / (σ / √n)Where: x is the data point you choose. μ is the mean. σ is the standard deviation.
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.
We know that Z=(x-μ)/σ. Previously, we knew x, μ, and σ and computed Z. Now, we know Z, μ, and σ, and we need to compute X, the value corresponding to the 90th percentile for this distribution. We can do this by rearranging the equation to solve for "x".
What is the formula to calculate raw score from z-score? ›5 Remember, raw score = mean + (z score)(standard error of the mean) Confidence Interval lower boundary raw score = mean + (-z score)(standard error of the mean) 30 + (-1.96)(.