Explanation:
As you found earlier, m = (T/(2π))² k.
So as T and k both increase, m increases. As T and k both decrease, m decreases.
So we can build a table and calculate m for each case assuming the extreme scenarios. In other words, we'll increase k by 10% and T by 0.007 s, then calculate the maximum m. Then, we'll decrease k by 10% and T by 0.007 s, then calculate the minimum m.
After we build the table, we see that the experimental range is 0.475 ≤ m ≤ 0.576. This interval contains the true value of m, 0.500.
