Commuting to College: An Analysis of a Suburban Campus on the Outskirts of Madrid

Table 6

Correlation between number of stops by postcode and number of individuals by transport mode in trip steps 1 and 2 for the Madrid community in the 2021-2022 course.

Transport type	Correlation step 1	Correlation step 2
Subway	0.70	0.6
Madrid urban bus	0.2	0.4
Urban bus	0.3	0.3
Interurban bus	−0.2	−0.2
Light subway	0.2	—
Commuter trains	0.2	—

A hyphen means some of the values to be analysed are constant, which results in a standard deviation equal to zero and, consequently, the correlation function returns an NA (not available) value.