Final answer:
The median is the middle value in an ordered data set, and the mode is the most frequently occurring number. In symmetric distributions, mean, median, and mode coincide, but in skewed distributions, the mean usually reflects skewing the most.
Step-by-step explanation:
The median is a measure of central tendency that indicates the middle value in a data set when the numbers are arranged in order. On the other hand, the mode refers to the most frequently occurring number(s) in a data set.
In a symmetrical distribution, the mean, median, and mode are all the same. However, if a distribution is skewed, the mean is the measure that tends to reflect the skewing the most. In a left-skewed distribution, the mean is less than the median, which is typically less than the mode.
When comparing these measures to the data set provided with the numbers 19, 11, 7, 11, the median and mode can be directly identified as 11. The other two numbers would require further calculation to determine which is the mean and which is the maximum or minimum. But considering a typical data set, we can identify the median and mode without performing any operations beyond ordering and counting the numbers.