Atlas Fishing line produces 10-lb test line. Twelve randomly selected spools are subjected to tensile-strength tests, and the results are given below.
9.8 10.2 9.8 9.4 9.7 9.7 10.1 10.1 9.8 9.6 9.1 9.7
(a) Is it misleading to advertise this as "IO-lb test line"? Explain what your results mean.
(b) Construct a 95% prediction interval for the tensile strength of the next randomly selected spool.
(c) Construct an interval that with 90% confidence will include the tensile strength of 95% of the spools.
(d) How large a second sample would be needed in order to construct a 99% confidence interval with length no more than 0.5?