Need this worked out in steps.

A machine cuts steel to length for nails. The mean length of a nail is 43 millimeters. There is concern that the settings of the machine producing the nails have changed. To test the claim, twelve nails (n = 12) were sampled. The mean of the sample is 41.5 and the standard deviation is 1.784. To test the claim at the 0.05 significance level,

1. What is degree of freedom?

2. what is the critical t-value value?

3. What is the t-value?

4. What is p-value?

5. What is your conclusion?