Tannin is a general term for certain nonvolatile phenolic substances in many fruits that provide an astringent sensation, in apple cider for example. There is some evidence to suggest the tannin level...

Tannin is a general term for certain nonvolatile phenolic substances in many fruits that provide an astringent sensation, in apple cider for example. There is some evidence to suggest the tannin level in apples is affected by the fertilizer regimen. A random sample of apples was obtained from both fertilized and unfertilized trees. The percentage of tannin was measured in each apple, and the data (sample size, sample mean, and sample standard deviation) are reported in the table below

a. Find a 95% confidence interval for the true mean tannin percentage in apples from fertilized trees.

b. Find a 95% confidence interval for the true mean tannin percentage in apples from unfertilized trees.

c. Is there any evidence to suggest the percentage of tannin is different in apples from fertilized and unfertilized trees?