In: Statistics and Probability
The center of a data set is a single value which we use for the whole data set, we usually use mean or median for the center.
A measure of spread or measure of dispersion, is used to describe the variability in a data set. Measures of spread include the range, quartiles and the interquartile range, variance and standard deviation.
Talking about percentiles, they are statistical measures of position. They do not measure a central tendency or a spread (dispersion) . Percentiles indicate the value below which a given percentage of observations in a group of observations fall. The 5th percentile is the value below which 5% of the observations may be found.
So, 5th percentile is neither spread or center. It is a measure of position.