document.write( "Question 1187787: Consider the situation of Review Exercise 5.95.
\n" ); document.write( "It has been determined that the sampling plan should
\n" ); document.write( "be extensive enough that there is a high probability,
\n" ); document.write( "say 0.9, that if as many as 2 defectives exist in the lot
\n" ); document.write( "of 50 being sampled, at least 1 will be found in the
\n" ); document.write( "sampling. With these restrictions, how many of the 50
\n" ); document.write( "items should be sampled?\r
\n" ); document.write( "\n" ); document.write( "Review Exercise 5.95.
\n" ); document.write( "A production process outputs items in lots of 50.
\n" ); document.write( "Sampling plans exist in which lots are pulled aside periodically and exposed to a certain type of inspection.
\n" ); document.write( "It is usually assumed that the proportion defective is
\n" ); document.write( "very small. It is important to the company that lots
\n" ); document.write( "containing defectives be a rare event. The current inspection plan is to periodically sample randomly 10 out
\n" ); document.write( "of the 50 items in a lot and, if none are defective,
\n" ); document.write( "perform no intervention.
\n" ); document.write( "(a) Suppose in a lot chosen at random, 2 out of 50 are
\n" ); document.write( "defective. What is the probability that at least 1
\n" ); document.write( "in the sample of 10 from the lot is defective?
\n" ); document.write( "(b) From your answer to part (a), comment on the
\n" ); document.write( "quality of this sampling plan.
\n" ); document.write( "(c) What is the mean number of defects found out of
\n" ); document.write( "10 items sampled?\r
\n" ); document.write( "\n" ); document.write( "I tried:
\n" ); document.write( "defective probability=0.2 (as many as 2 defective=>so I thought 1 and 2 defective)
\n" ); document.write( "no defective=0.1
\n" ); document.write( "p(defective)=2/50
\n" ); document.write( "p(no defective)=48/50
\n" ); document.write( "p(at least 1 defective)=1-p(no defective)=1-(48C10)/(50C10)=1-0.6367=0.3633\r
\n" ); document.write( "\n" ); document.write( "and here I get confused.\r
\n" ); document.write( "\n" ); document.write( "P(X<=2)=P(2)+P(1)+P(0)=\"%2850%21%2F48%212%21%29%2A0.9%5E2%2A0.1%5E48\"+\"%2850%21%2F49%211%21%29%2A0.9%5E1%2A0.1%5E49\"+\"%2850%21%2F50%210%21%29%2A0.9%5E0%2A0.1%5E50\"=\r
\n" ); document.write( "\n" ); document.write( "or is 0.9 supposed to be 2/50 and 0.1 supposed to be 48/50 ???\r
\n" ); document.write( "\n" ); document.write( "Thank you for your time :)
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Algebra.Com's Answer #818934 by ikleyn(52805)\"\" \"About 
You can put this solution on YOUR website!
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