Which of the following is evidence that the universe began with the big bang theory

Ais useful when you need a simple machine to you separate two things. a. lever b. screw c. pulley d. wedge

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

What are two different ways you could find the value of a? explain these methods.