Applied Biometrics for Plant Sciences
PlSci 547 - Spring 2005
Take Home Questions #1
Due by Wednesday February 2, 9:30am
Answer all 6 questions
A total of 100 points are available
All answers should be typed 1.5 row spacing
Grade points from each question are shown in
bold square parenthesis
A Bonus Question is available for an additional 10 points
Late return of answers will be penalized by 10% per day late
Unless a late return has been previously agreed
2
1.
Two friends (Hortwog and Scumworth) decided to have a small wager on a game
of chance while biding the time away at the 'Half-way Inn' in down town
Looserville. The game was simple and involved each person (in turn) tossing an
unbiased silver dollar. The first player to correctly call (heads or tails) the toss
twenty (20) times was the winner and would receive the $100 wager ($50 put in
by each player). The game was going splendidly until the score was 16 wins to
Hortwog and 17 wins to Scumworth. Just at that moment the phone rang and it
was relayed that Scumworth's dear wife had gone into labor with their soon to be
first born. Scumworth had to leave immediately without finishing the game. As
Scumworth dashed from the Inn, Hortwog shouted "how should we divide the
wager?" "You take $34.37 and I get the rest" was Scumworth's reply. Explain
how Scumworth came to this solution of how to divide the wager. Alternatively,
offer an alternative solution to fairly divide the $100 between the two players. [20
points].
2.
Economic losses from worm parasite infections of cattle can be significant if not
treated properly. Calves under one year of age are much more susceptible than are
older cattle, which may have been frequently exposed to infection and built up
some form of immunity.
Adult worms in cattle produce eggs that are passed in the manure. Eggs hatch,
producing larvae that develop and move up into the pasture grasses where cattle
consume them. Eggs can survive winter weather in pasture and hatch in warm
spring conditions. Infection is most likely to occur when temperatures are
between 10o and 20o F. and after rainfall.
De-worming early is the season can greatly reduce the risks of infection.
However, in Scotland, where some of farmers in the community are considered
overly 'thrifty', the cost of de-worming compounds can make the process costly,
particularly if the risk of infection is considered to be low. Dr. Douglas McPatty,
a well know Scottish veterinarian has studied this for some time and has
discovered that he can determine the need to treat calves for internal parasites by
examining the manure of calves. He found that it is not necessary to treat all
calves within a herd when less than 5 of 40 manure droppings examined contain
parasite eggs. He also found from his sifting through cow manure that nationwide the probability of finding parasite eggs in a single cow dropping was 0.083.
Willie 'the Mean' from Bovineville has a dairy herd in southern Ayeshire (where it
always rains) and he is desperate to decide whether to treat his cattle for parasite
infection. What is the probability that Willie will have to treat his herd? [15
points].
3
3.
A properly designed experiment was conducted whereby three canola (Brassica
napus) cultivars ('Sunshine', 'Moonshine', and 'Dull') were planted in each with
three different insecticides and a no-insecticide control. The three insecticides
were 'Early Dawn' which controlled only early season insect pests, 'Mid-life Crisis'
which controlled insects late in the season, and 'Bugoff' which provided all season
insect control. Early Dawn is a seed treatment costing $10 ha-1, Mid-life Crisis
and Bugoff are both foliar applied and cost $15 and $20 ha-1, respectively. The
experiment was grown at two locations, Moscow, ID, and Pullman, WA. In 2004,
canola farm gate prices were $0.24 kg-1.
Results from yield assessments of the trial are shown below. Using only first
order statistics, describe and explain the results and offer suggested advice to
canola growers for the 2005 growing season. Present your answer in the form of a
Results and Discussion section of a scientific journal article. [25 points].
Cultivar
Sunshine
Moonshine
Dull
4.
Insecticide
treatment
Early Dawn
Mid-life Crisis
Bugoff
Early Dawn
Mid-life Crisis
Bugoff
Early Dawn
Mid-life Crisis
Bugoff
Moscow
Pullman
-1
-------------- kg ha ------------900
1,435
1,450
1,011
1,598
1,543
1,129
1,299
1,382
1,332
1,401
1,434
600
1,557
785
658
1,425
1,525
Calculate the mean, variance and standard deviation weekly weight gain of 80
beef steers (kg).
123
133
143
130
144
142
135
143
136
150
154
151
111
140
151
118
155
152
142
143
137
147
109
150
129
136
146
167
115
125
133
142
151
161
137
148
143
113
143
155
149
145
132
108
133
144
133
105
126
137
121
148
138
112
129
160
147
112
133
142
111
125
139
119
135
142
123
145
131
112
143
159
131
154
138
137
143
123
130
145
Using this information, estimate the probability of selecting a single steer at
4
random from this sub-population with weekly weight gain:
(a) Greater than 158 kg;
(b) Greater than 130 kg and less than 140 kg. [15 points].
How many steers would need to be screened to be 99% sure that at least one had a
weekly weight gain greater than 158 kg [5 points].
5.
Outline all the features you would request be included in a computer software
system specifically designed for your own specific research, and indicate why
each component would be desired. [10 points].
6.
Outline the goals of your graduate student research and indicate how you think
attending this biometrics class will help you in completing your degree. [10
points].
Bonus Question
Write a question that I might consider including in the first biometrics test in 2007.
The question should be notably different from any given above but should be
directly related to the work we have done in class so far.
[5 bonus points].