Solution

Solution

Measures of central tendency identify the "center" or typical value in a dataset. The three main measures are mean, median, and mode.

Mean is the average: add the numbers and divide by how many there are.

Median is the middle value when the numbers are in order. For an odd count, it is the exact middle ($70$ in $50, 60, 70, 80, 90$). For an even count, it is the average of the two middle numbers:

Mode is the number that appears most often. If scores are $50, 60, 70, 70, 90$, the mode is $70$. If $60$ and $70$ both appear twice, there are two modes: $60$ and $70$.

These measures describe the typical score. Spread around that center is described separately by variance and standard deviation.