Silly Mistakes 1

Question: 
If f (x) = 3x² + 2x +1, find the first derivative of f at x = 0.

Answers:
1st version:
f '(x) = 6x + 2 = 6(0) + 2 = 2 

2nd version:
f '(x) = 6x + 2 
f '(0) = 6(0) + 2 = 2

The truth  f '(x) ≠ 2 but f '(0) = 2.

Interprete Minitab Output for Multiple Comparison.

When the null hypothesis is rejected (the result showed a significance difference), we want to know where the difference among the means is. Which group of mean causes this difference? We can do further analysis by carry out multiple comparisons. The most commonly used methods are LSD and Tukey's tests.

Example: Concentration of Mercury.

Since H0 is rejected, there is a difference in mean concentration of mercury in the three regions. We can do further analysis to know which region mean causes the difference.

Conclusion: Only one and third comparisons exhibited significant difference in mercury concentration. Region 2 has the highest concentration of mercury.