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Variance
Variance Variance is a measure of how spread out a set of data is. It is a measure of how different each data point is from the mean. In simpler terms, it t...
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Variance Variance is a measure of how spread out a set of data is. It is a measure of how different each data point is from the mean. In simpler terms, it t...
Variance
Variance is a measure of how spread out a set of data is. It is a measure of how different each data point is from the mean. In simpler terms, it tells us how much the data values vary from the average.
Imagine a bell curve. The mean is the average point on the curve, and the variance is the amount of spread out the curve is. A bell curve with a high variance would look more spread out than a bell curve with a low variance.
Key points about variance:
Variance is a measure of dispersion, not a measure of central tendency. This means that the mean and variance can be different for a set of data.
Variance is a positive quantity, meaning that a higher variance indicates more spread out data.
Variance is used to compare the variability of different datasets. For example, if two datasets have the same mean but different variances, then the dataset with the higher variance would have more variability.
Example:
Let's say we have a dataset of exam scores. The mean score is 80 and the standard deviation is 10. This means that the scores are on average 10 points above or below the mean, with 90% of the scores falling within one standard deviation above or below the mean.
Therefore, the variance of the exam scores would be 100. This indicates that the scores are very spread out, with a high variance