<span>Residual value is the difference between the observed value of the dependent variable (y) and the predicted value (ŷ) in a data set.
i.e. Residual value = given value - predicted value
From the table, the residual value corresponding to a has 4.1 as the given value and 4.5 as the predicted value.
Therefore, a = 4.1 - 4.5 = -0.4
Similarly, </span><span>the residual value corresponding to b has 7.2 as the given value and 7.05 as the predicted value.
Therefore, b = 7.2 - 7.05 = 0.15
</span>
Therefore, a = -0.4 and b = 0.15
Well 500 mm = 50 cm so if you add both segments together you will get a 50+30=80cm segment