Home > What are Zscores?

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Sometimes we want to do more than summarize a bunch of scores. Sometimes we want to talk about particular scores within the bunch. We may want to tell other people about whether or not a score is above or below average. We may want to tell other people how far away a particular score is from average. We might also want to compare scores from different bunches of data. We will want to know which score is better. Zscores can help with all of this.
They Tell Us Important Things
ZScores tell us whether a particular score is equal to the mean, below the mean or above the mean of a bunch of scores. They can also tell us how far a particular score is away from the mean. Is a particular score close to the mean or far away?
If a ZScore….
ü Has a value of 0, it is equal to the group mean. ü Is positive, it is above the group mean. ü Is negative, it is below the group mean. ü Is equal to +1, it is 1 Standard Deviation above the mean. ü Is equal to +2, it is 2 Standard Deviations above the mean. ü Is equal to 1, it is 1 Standard Deviation below the mean. ü Is equal to 2, it is 2 Standard Deviations below the mean. ZScores Can Help Us Understand…
How typical a particular score is within bunch of scores. If data are normally distributed, approximately 95% of the data should have Zscore between 2 and +2. Zscores that do not fall within this range may be less typical of the data in a bunch of scores. ZScores Can Help Us Compare…
Individual scores from different bunches
of data. We can use Zscores to standardize scores from different groups of
data. Then we can compare raw scores from different bunches of data.
