Hi I really don't understand this question can you help me with the solution?

Question 5: (from chapter 10) A genetic engineering company claims that it has developed a genetically modified tomato plant that yields on average more tomatoes than other varieties. A farmer wants to test the claim on a small scale before committing to a full-scale planting. Ten genetically modified tomato plants are grown from seeds along with ten other tomato plants. At the season's end, the resulting yields in pound are recorded as below. Sample 1 Sample 2 Generically Modified Regular 20 21 23 21 27 22 25 18 25 20 25 20 27 18 23 25 24 23 22 20 a. Construct the 99% confidence interval for the difference in the population means based on these data. b. Test, at the 1% level of significance, whether the data provide sufficient evidence to conclude that the mean yield of the genetically modified variety is greater than that for the standard variety