answer with explanation

Ketkar and associates developed a new analytical method for measuring trace levels of atmospheric gases. The analysis of a sample containing 40.0 ppt 2-chloroethylsulfide yielded the following results: 43.3 34.8 31.9 34.4 37.8 31.9 42.1 33.6 35.3 Determine whether there is a significant difference between the experimental mean and the expected value at alpha = 0.05. In the box give the calculated value of texperimental to 3 significant figures