A Note about the Calculations & Decimal Precision
The values presented in the graphs above are approximations derived from the work of
Abramowitz & Stegun. If you need precision to more that 4 decimals you are encouraged to
consult multiple published tables of Z-Values.
| May 28, 2009 | Tom wrote: |
| seen a couple people ask the same question, but i'm looking for an actual formula to convert the Z-scores to percentiles. can't find anywhere on the internet that has it. |
| April 17, 2009 | troy percival wrote: |
| i am writing a database and need to make calculations to turn z scores into percentages. I am enquiring if you can help me with the formula that operates the calculator. Many thanks |
| March 9, 2009 | Denise wrote: |
| for a population with a mean of 80 and standard deviation of 12, what is the z-score corresponding to x=71? |
| March 3, 2009 | Susan wrote: |
| 6. An aptitude test has a mean of 220 and standard deviation of 10. find the corresponding z score for: a) a test score of 232 b) a test score of 212 |
| January 26, 2009 | anonomous wrote: |
| 6. An aptitude test has a mean of 220 and standard deviation of 10. find the corresponding z score for: a) a test score of 232 |
| October 16, 2008 | Verena wrote: |
| Hi, I have been using your tool to calculate percentiles from z-score values. Until like a week ago, it worked perfectly fine, but now, when I enter a z-score of 3, one-sided, the value under 100% should be the higher one (in fact, it should be close to 99). Now, however, the higher number is being reported under the % of area section - how can that be? |
| September 11, 2008 | Ivy wrote: |
| Your MS class all took the practice clinical certification exam. The following is a listing of the raw scores that you and your friends received. Compute the z scores for these raw scores where the mean is 55 and the standard deviation is 2.5. What is a “z” score? What does it tell you? Scores: 60, 72, 48, 53, 56, 51, 50.5, 59.5 x (observation) = 8 mean = 55 standard deviation = 2.5 z = Observation - Mean Standard Deviation = 8 – 55 / 2.5 = - 18.8 I don't have a book to find the z score for -18.8. I am not even sure if that is possible to get a z score for -18.8. Thank you for your help. |
| June 24, 2008 | Cindy Searcy wrote: |
| How would I figure a z-score if the mean was 11.9, the std. deviation is .4 and I want to be 95% sure that a bag of chips did not weigh 12 Oz. as specified on bag, and I weighed 30 Bags? |
| May 15, 2008 | Alex wrote: |
| hey, can send me the formula that happens in the BG? |
| April 30, 2008 | Steve Kelner wrote: |
| I can't seem to do a negative z-score. Otherwise outstanding! |
| March 19, 2008 | Justin wrote: |
| I have a normal distribution of Homeruns per week with mean 8.3 and standard deviation of 1.1. My team is projected to hit 10 homeruns in a week while my opponent's team is projected to only hit 8. What is the likelyhood of my team hitting more homeruns during the coming week? I am guessing P(8 |