Please help me to understand this problem:

Two suppliers manufacture a plastic gear used in a laser printer. The impact strength of these gears, measured in foot-pounds, is an important characteristic. A random sample of 13 gears from supplier 1 results in X1 = 281 and $1 = 13, while another random sample of 15 gears from supplier 2 results in X2 = 325 and 52 = 21. Is there evidence to support the claim that supplier 2 provides gears with higher mean impact strength? No. Use @ = 0.US, and assume that both populations are normally distributed but the variances are not equal. What is to for this test? to Round your answer to two decimal places (e.g. 98.76)