statistic
posted by Anonymous .
One operation of a mill is to cut pieces of steel into parts that will later be used as the frame for front seats in an automobile. The steel is cut with a diamond saw and requires the resulting parts to be within ±0.005 inch of the length specified by the automobile company. The data in the file Steel comes from a sample of 100 steel parts. The measurement reported is the difference in inches between the actual length of the steel part, as measured by a laser measurement device, and the specified length of the steel part. For example, the first value, 0.002, represents a steel part that is 0.002 inch shorter than the specified length.
a. Construct a percentage histogram.
b. Is the steel mill doing a good job in meeting the requirements set by the automobile company? Explain.

nevermind above question, this question please:
Suppose there are three balls in a box. On one of the balls is the number 1, on another is the
number 2, and on the third is the number 3. You select two balls at random and without
replacement from the box and note the two numbers observed. The sample space S consists of
the three equally likely outcomes {(1, 2), (1, 3), (2, 3)}. Let X be the sum of the numbers on the
two balls selected.
Referring to the information above, the variance of X is... (EXPLAIN)