it is shaped roughly like a bell... a bell curve.
17.7 and 20.9
The standard deviation for the Woodcock-Johnson III Tests of Achievement is typically set at 15. This is consistent with many standardized tests, which use a mean of 100 and a standard deviation of 15 to represent scores on a normal distribution. This allows for the interpretation of individual test scores in relation to the broader population.
When the normal curve is plotted using standard deviation units, each with a value of 1.00, it is referred to as the standard normal distribution. In this distribution, the mean is 0 and the standard deviation is 1, allowing for easy comparison of different data sets by transforming them into z-scores. The standard normal distribution is often represented by the symbol Z.
The answer depends on the degrees of freedom (df). If the df > 1 then the mean is 0, and the standard deviation, for df > 2, is sqrt[df/(df - 2)].
Z-scores standardize data from various distributions by transforming individual data points into a common scale based on their mean and standard deviation. This process involves subtracting the mean from each data point and dividing by the standard deviation, resulting in a distribution with a mean of 0 and a standard deviation of 1. This transformation enables comparisons across different datasets by converting them to the standard normal distribution, facilitating statistical analysis and interpretation.
17.7 and 20.9
It is 68.3%
If the standard deviation of 10 scores is zero, then all scores are the same.
Assuming a normal distribution 68 % of the data samples will be with 1 standard deviation of the mean.
All the scores are equal
mean
T-scores and z-scores measure the deviation from normal. The normal for T-score is 50 with standard deviation of 10. if the score on t-score is more than 50, it means that the person scored above normal (average), and vise versa. The normal for Z-score is 0. If Z-score is above 0, then it means that person scored above normal (average), and vise versa.
The standard deviation for the Woodcock-Johnson III Tests of Achievement is typically set at 15. This is consistent with many standardized tests, which use a mean of 100 and a standard deviation of 15 to represent scores on a normal distribution. This allows for the interpretation of individual test scores in relation to the broader population.
None.z-scores are linear transformations that are used to convert an "ordinary" Normal variable - with mean, m, and standard deviation, s, to a normal variable with mean = 0 and st dev = 1 : the Standard Normal distribution.
No, it is called the absolute deviation.
In general, you cannot. If the distribution can be assumed to be Gaussian [Normal] then you could use z-scores.
The cumulative probability up to the mean plus 1 standard deviation for a Normal distribution - not any distribution - is 84%. The reference is any table (or on-line version) of z-scores for the standard normal distribution.