Do i use the t-value of 3.4995 for the 99% confidence interval or the z-value of 2.576? This is the question below:

Make a 99% confidence interval of the number of calories in 3 ounces of French fries based on a sample of 8 batches of French fries, weighing 3-ounce each, taken from different restaurants. The sample has a mean of 244.5 and a sample standard deviation, s, of 21.7. Interpret the results.