A field researcher is gathering data on the trunk diameters of mature pine and spruce trees in a certain area. The following are the results of his random sampling. Can he conclude, at the 0.10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree?
Pine trees
Spruce trees
Sample size
25
35
Mean trunk diameter (cm)
55
48
Sample variance
100
140
What is the test value for this hypothesis test?
Test value: