In an area where a river has cut deep into Earth, there are several layers of very different rock exposed. The oldest rock layer is most likely to be layer that is A. Below the other layers

B. The thickest layer

C. The most rich in fossils

D. Igneous intrusive rock

The force acting on a beam was measured under the same operating conditions and a sample of 5 data points was collected. this process was repeated by 3 observers. the pooled standard deviations of these 3 data sets was 1.21. determine the true mean force using all pooled data (with a 95% probability). the result should look like this: true mean = mean +/- margin of error