To determine whether it is true or false that "If the correlation coefficient is 0.7 or lower, it may be appropriate to fit a non-linear regression," we need to assess the given correlation coefficient value.
Given that the correlation coefficient is 0.7, we need to check if it meets the condition stated:
1. Evaluate whether 0.7 is lower than or equal to 0.7.
2. Since 0.7 is exactly equal to 0.7, the condition is satisfied.
3. Therefore, the statement that "If the correlation coefficient is 0.7 or lower, it may be appropriate to fit a non-linear regression," is true.
Thus, the answer is:
True
