"Productivity" is a term you hear quite often in news reports about the economy. Productivity isnt everything, but in the long run it is almost everything. A countrys ability to improve its standard of living over time depends almost entirely on its ability to raise its output per worker.

Productivity measures how efficiently production inputs, such as labor and capital, are being used in an economy to produce a given level of output. Knowledgeable, skilled workers with the proper tools such as computers or manufacturing equipment result in high productivity.

ThisProductivityExcel file shows the percent change in worker output per hour from the previous quarter for the United States from 1988 through 2008.

Question 1. Make a histogram of the productivity data in the above file. Select the histogram below that is closest in shape to the histogram of the productivity data.

Histogram C

Histogram D

Histogram A

Histogram B

Question 2. These data can be approximated quite well by a N(3.4, 3.1) model. Economists become alarmed when productivity decreases. According to the normal model what is the probability that the percent change in worker output per hour from the previous quarter is more than0.8standard deviations below the mean?

Question 3. What is the probability that the percent change in worker output from the previous quarter is between-1.715and4.02? Use the normal model mentioned at the beginning of question 2.