A student wants to check his method for KHCO, determination by analyzing a sample known to contain 48.82% (m/m) KHCO3. For the five-replicate determinations of % (m/m) KHCO, in this unknown standard, the following results were obtained: 48.71% 48.59% 48.62% 48.44% 48.58% Is the mean obtained for these five data significantly different from the true value (48.82 % m/m) at the 95% confidence level? Degrees of fredom 1 2 3 4 5 6 Values of t for the 95% confidence interval t 12.71 4.30 3.18 2.78 2.57 2.45