# Past Exam for STAT 400 - APPLIED PROB & STAT I at Maryland (UMD)

## Exam Information

 Material Type: Final Professor: Staff Class: STAT 400 - APPLIED PROB & STAT I Subject: Statistics and Probability University: University of Maryland Term: Fall 1997 Keywords: Central Limit TheoremIn/on/at a PlaceFollowing ProblemThe IndependentResponse TimeDistributionNo CorrelationLaw of Large NumbersRandom VariableRandom Sample

## Sample Document Text

STAT 400, Final Examination Dec. 18, 1997, Thur. 10:30 - 12:30 AM Show your work in each of the following problem.s. 1. (20%) Suppose the response time to a particular editing command of a computer time-sharing system iE: normally distributed with standard deviation cr = Hi millisec. (a) Construct a 90% confidence interval for the mean response time f1, based on a random sample of 25 response times with a sample average of 24.3. (b) Calculate the sample size n to ensure that the resulting 90% CI has a length 7. 2.(20%) Suppose the hardness of a certain alloy is normally distributed with mean /-l = 65 and standard deviation cr = 4.7. (a) A speciman is acceptable only if its harness exceeds 159. Compute the probability that a randomly chOSEn specimen has an acceptable hardness. (b) Derive the probability that eight or more of ten independently selected specimens have acceptable hardness ? (Round off numberical values to the second decimal place.) 3.(20%) Let X be a random variable ...

## Related Documents

Combinations Exam
Combinations Exam
Random Sample Notes
Concentrated Exam
The Independent Exam
The Independent Exam
Probabilities Exam
Either...or Exam