Question 1182179: Question 1 [7 marks]
a) A coin is tossed three times, calculate the probability that exactly two of the three tosses
results in heads.
b) In how many ways can 12 different amino acids be arranged into a polypeptide chain
of five amino acids.
c) A farmer’s herd of cattle consists of three Nguni bulls, two Nguni cows, four Bonsmara
bulls, four Bonsmara cows, five Hereford bulls and four Hereford cows. What is the
probability of selecting at random:
1. A Nguni cow?
2. A cow, if it is a Nguni.
3. A Nguni, if it is a cow.
4. An Angus bull.
d) A Kwazulu-Natal farmer in the area of the Brucellosis outbreak has a herd of 25 cows. Page 2 of 4
Among them 20 are infected and 5 are not. Two cows will be selected from the herd
and tested for Brucellosis. Calculate the probability that the second animal is infected,
given that the first selected animal is infected.
Question 2 [3 marks]
A cage contains eight rats, three of them are white (W) and five of them are brown (B). A
second cage contains five rats, two white and three brown; and a third cage contains five rats,
three white and two brown. If one rat is randomly selected from each cage,
a) What is the probability that all three rats are white?
b) What is the probability that exactly two of the three will be brown?
c) What is the probability of selecting at least one black rat?
Question 3 [3 marks]
A group of dogs consists of three brown females, two brown males, four white females, four
white males, five black females and four black males. What is the probability of selecting at
random:
a) A brown female dog?
b) A female dog, if the dog is brown?
c) A brown dog, if the dog is female?
Page 3 of 4
Question 4 [3 marks]
Three flower seeds are selected from a package that contains 5 seeds for white, 6 seeds for red,
and 4 seeds for yellow flowers. What is the probability that:
a) All 3 seeds produce red flowers?
b) The 3 seeds produce flowers of different colours?
c) The 3 seeds produce flowers of the same colour?
Question 5 [3 marks]
A farm dam contains the following numbers of fishes.
a) What is the relative frequency of each species?
b) Assuming that each individual fish has the same probability of being encountered,
estimate the probability of encountering an African sharptooth catfish.
c) Assuming that each individual fish has the same probability of being encountered,
estimate the probability of encountering a fish belonging to the genus Labeobarbus.
Species Number
African sharptooth catfish (Clarias gariepinus) 15
European carp (Cyprinus carpio) 6
Grass carp (Ctenopharyngodon idella) 9
Smallmouth yellowfish (Labeobarbus aeneus) 8
Largemouth yellowfish (Labeobarbus kimberleyensis) 4
Orange River Mudfish (Labeo capensis) 6
Page 4 of 4
Question 6 [2 marks]
Twelve rats are injected with a certain drug and the number of rats that die within 2 hours is
recorded. Suppose that the probability that exactly 9 rats die is ଵ
ହ
and the probability that 10, 11
or 12 rats die is
ଵଶ
. Find the probability that:
a) 9 or more rats die.
b) 8 or less rats die.
Answer by greenestamps(13200)   (Show Source):
You can put this solution on YOUR website!
This forum is not a place where you can dump your entire homework assignment and have someone else work the problems for you.
The rules of the forum are...
(1) ONE problem per post
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