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z scores

IQ scores in the population have a mean of 100 and a standard deviation of 15. If Bob has an IQ of 83, what percent of people have scores lower than him? If Sally has an IQ of 97, what percent of people have scores higher than her? What percent of people have IQs between 80 and 120?

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Tovi Hansen

Lvl 1
5y ago
Updated: 10/17/2024

If a random variable X has a normal distribution with mean m and standard error s, then the z-score corresponding to the value X = x is (x - m)/s.

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Jamir Kuhn

Lvl 10
3y ago

What else can I help you with?

Related Questions

When to you use a z scores or t scores?

If the distribution is Gaussian (or Normal) use z-scores. If it is Student's t, then use t-scores.


Are normal scores the same as z-scores?

They should be.


What is one advantage of transforming X values into z-scores?

True or False, One major advantage of transforming X values into z-scores is that the z-scores always form a normal distribution


Is the Z-test the same as Z-scores?

No, the Z-test is not the same as a Z-score. The Z-test is where you take the Z-score and compare it to a critical value to determine if the null hypothesis will be rejected or fail to be rejected.


Are all standard scores z-scores in statistics?

Yes, although the z-scores associated with p-values of 0.01 and 0.05 have special significance, perhaps mostly for historical reasons, all possible z-scores from negative infinity to positive infinity have meaning in statistical theory and practice.


What is the formula for z scores?

Z = (x minus mu) divided by sigma.


In a standard normal distribution about percent of the scores fall above a z score of 300?

A Z score of 300 is an extremely large number as the z scores very rarely fall above 4 or below -4. About 0 percent of the scores fall above a z score of 300.


How do you find normal distribution of z-scores?

z-scores are distributed according to the standard normal distribution. That is, with the parameters: mean 0 and variance 1.


What z-score separates the top 10 percent from the rest of the scores?

z = 1.281551


Do z-scores have a units of measure?

No, they do not. They are pure numbers.


How can you use a z score to determine outliers?

Best to use a histogram i think! z scores can probably be used too however they seem more a method of how to transform outliers in workable scores.


Compare and contrast the functions of z-scores t-scores and percentile ranks?

Z-scores, t-scores, and percentile ranks are all statistical tools used to understand and interpret data distributions. Z-scores indicate how many standard deviations a data point is from the mean, allowing for comparison across different datasets. T-scores, similar in function to z-scores, are often used in smaller sample sizes and have a mean of 50 and a standard deviation of 10, facilitating easier interpretation. Percentile ranks, on the other hand, express the relative standing of a score within a distribution, showing the percentage of scores that fall below a particular value, thus providing a different type of comparison.