Conductivity is one important characteristic of glass. The article “Structure and Properties of Rapidly Quenched Li2O-Al2O-Nb2O5 Glasses” (J. Amer. Ceramic Soc., 1983:

890–892) reports the accompanying data on x
Li2O content of a certain type of glass and y
conductivity at 500 K.

x | 19 20 24 27 29 30 y | 108.0 107.1 107.2 106.7 106.2 106.8 x | 31 39 40 43 45 50 y | 105.8 105.3 106.0 104.7 105.4 105.1

(This is a subset of the data that appeared in the article.)

Propose a suitable model for relating y to x, estimate the model parameters, and predict conductivity when Li2O content is 35.