Page 294 - DMTH404_STATISTICS

Statistics

Notes 21.5 Self Assessment

1. If the random variable X measures the toxicity of a drug, a doctor may wish to have a
knowledge t of the .................. for the hean of X in order to prescribe this dmg.

2. If the .................. X measures the waiting times at the emergency room of a large city
hospital, one may be interested in the mean waiting time at this emergency room.

21.6 Review Questions

1. Let X , X , . . . , X be a random sample from a normal population, N (,  ). We wish to
2
1 2 n
obtain a (1 – ) level confidence interval for .
2
2. Let X , X , . . . , X be a random sample, from N(,  ). It is desired to obtain a confidence
1 2 n
interval for  when  is unknown.
2
2
3. Let X , X , . . . , X be a random sample from a normal population, N (,  ). We wish to
1 2 n
obtain a (1 – ) level confidence interval for .
4. Let X , . . . , X and Y , . . . , Y denote respectively independent random samples from the
1 2 1 m
two independent distributions having respectively the probability density functions N( ,
1
2
2
 ) and N( ,  ). We wish to obtain a confidence interval for  –  .
2  2
2
5. Let X , X , . . . , X be a random sample from a normal population, N (,  ). We wish to
1 2 n
obtain a (1 – ) level confidence interval for .
6. Let X , X , . . . , X be a random sample from a normal population, N (,  ). We wish to
2
1 2 n
2
obtain a (1 – ) level confidence interval for .
Answers: Self Assessment
1. upper bound 2. random variable
21.7 Further Readings

Books Sheldon M. Ross, Introduction to Probability Models, Ninth Edition, Elsevier
Inc., 2007.
Jan Pukite, Paul Pukite, Modeling for Reliability Analysis, IEEE Press on
Engineering of Complex Computing Systems, 1998.

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