Determine the direction of equilibrium shift due to a decrease in the equilibrium constant:
If a temperature change causes the equilibrium constant to become smaller in value, in which direction does the temperature change cause the equilibrium to shift?
The temperature change causes the equilibrium to shift to the right.
The temperature change causes the equilibrium to shift to the left.

Step 1 ：Determine the direction of equilibrium shift due to a decrease in the equilibrium constant.

Step 2 ：The equilibrium constant (K) of a reaction is a measure of the ratio of the concentrations of the products to the reactants at equilibrium.

Step 3 ：If the equilibrium constant decreases, it means that the ratio of the concentrations of the products to the reactants is decreasing.

Step 4 ：This implies that the reaction is shifting in the direction of the reactants, or to the left.

Step 5 ：Therefore, a decrease in the equilibrium constant due to a temperature change would cause the equilibrium to shift to the left.

Step 6 ：Final Answer: The temperature change causes the equilibrium to shift to the \(\boxed{left}\).