MA4151 APPLIED PROBABILITY AND STATISTICS FOR COMPUTER SCIENCE ENGINEERS
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Two marks
1. Define random variables
2. The mean and variance of binomial distribution are 5 and 4. Find the
distribution
3. Define t-distribution
4. Define Type I and Type II errors
10 marks
5. An electrical firm manufactures light bulbs that have a life before burn
out that is normally distributed with mean equal to 800 hrs and a
standard deviation of 40 hrs. Find the (i) the probability that a bulb
more than 834 hrs. (ii) the probability that bulbs burns between 778 and
834 hrs.
MA4151 APPLIED PROBABILITY AND STATISTICS FOR COMPUTER SCIENCE ENGINEERS
Question Bank
6. A certain drug is claimed to be effective in curing colds. In an
experiment on 164 people with cold, half of them were given drug and
half of them given sugar pills. The patient’s reaction to the treatment
are recorded in the following table
Help Harm No Total
ed ed effec
t
Drug 52 10 20 82
Sugar 44 12 26 82
pills
Total 96 22 46 164
On the basis of this data can it be concluded that there is a significant difference in the effect
of the drug and sugar pills?
7. A Manufacturer of ball pens claims that a certain pen the Manufactures
has a mean writing life of 400 pages with a standard deviation of 20
pages. A purchasing agent selects a sample of 100 pens and puts them
for test. The mean writing life for the sample was 390 pages. Should the
purchasing agent reject the manufactures claim at 5% level? Table
value of z at 5% level is 1.96 for two tail tests and 1.64 approximately
for one tail test.
MA4151 APPLIED PROBABILITY AND STATISTICS FOR COMPUTER SCIENCE ENGINEERS
Question Bank
8. The saving bank account of a customer showed an average balance of
Rs.150 and a standard deviation of Rs.50. Assuming that the account
balances are normally distributed.
1. What percentage of account is over Rs. 200?
2. What percentage of account is between Rs.120 and Rs.170?
3. What percentage of account is less than Rs.75?.
MA4151 APPLIED PROBABILITY AND STATISTICS FOR COMPUTER SCIENCE ENGINEERS
Question Bank
MA4151 APPLIED PROBABILITY AND STATISTICS FOR COMPUTER SCIENCE ENGINEERS
Question Bank
