Hi, yesterday I sat my Stats exam at Reading University. One of the questions was about Linear Regression lines. For the data given there were was one x value(namely 5) corresponding to two y values (as in when x=5 y=3.5 and x=5 y=3.7). Now some of the values had for example 3 and 3.5, which made me think maybe this was a mistake in the paper. Can linear regression lines have points which correspond with two values? Obviously when you plot your line of best fit then two values also correspond with the same value which meant one point didn't fit the line properly.

Just wondering really