ENVX3002代做、via Turnitin代写、R语言代做、R程序设计代写

日期：2019-04-12 09:42

ENVX3002: Statistics in the Natural Sciences, 2019

Assessment 2

DUE DATE: 5PM Friday 12 April – online submission.

WEIGHTING: 12.5%, mark is out of 20

1.The assessable exercises you submit must be your own work

2.All answers are to be submitted via Turnitin as a Word file.

3.Combined answers should not be longer than 6 pages.

4.Marks will be deducted for particularly sloppy presentation.

5.Include your R code either in situ in the document, or as an Appendix

Problem Question

On the following pages is a description of a study done to test anti-inflammatory drugs on pigs.  The control drug given was saline.  Please read the following but you are only to concentrating on one outcome.  These are either the behavioural outcomes of scratching or social given.  You are to choose one of these to report.

Blocking

When you attempted analysis with blocking you were more likely to be using ANOVA.  When you have to use more advanced models you will have to include the blocking structure in the model, but remember to treat the blocks as you would normally treat them (don’t use interactions unless indicated by the structure, don’t drop them from the model, don’t comment on their significance).

Data

Data are in two separate csv file.  The variables are Pig, Shed, Pen, Day, Tag, treatment, behaviour.  The tag is just a colour code for treatment, so don’t include that in the model or you will have two variables that say the same thing (try it – it doesn’t work).

Experiment 3 - Comparison of three anti-inflammatory drugs in pigs

Aim:

To determine if the anti-inflammatory medicaments ketoprofen, meloxicam, and dexamethasone improve welfare in animals suffering from inflammation.

The anti-inflammatory drugs ketoprofen, meloxicam and dexamethasone have the benefit of improving animals with inflammation.

Hypothesis:.

Ho: Ketoprofen, meloxicam and dexamethasone have the same analgesic and anti-inflammatory effect on induced inflammation in weaner pigs when compared to pigs not administered an anti-inflammatory drug.

Ha: Ketoprofen, meloxicam and dexamethasone have a greater analgesic and anti-inflammatory effect on induced inflammation in weaner pigs when compared to pigs not administered an anti-inflammatory drug.

YES

Methods

Animals

Thirty-two 10-week-old male pigs were housed in a facility. Pigs were allowed 7 days to acclimatise to the environment. Accommodation was in two sheds, and within each shed there were 4 pens of pigs. Each pen consisted of 4 pigs, one pig from each treatment group (control, meloxicam, ketoprofen, and dexamethasone). Pigs were randomly assigned to pens with pigs of a similar weight.

Each pig received a subcutaneous injection of Improvac behind each ear. They were then treated with one of saline, ketoprofen, meloxicam or dexamethasone daily for 3 days

1.Weight Change

a.Pigs were weighed by digital scales before treatment, and again at the end of the trial. Weight change was calculated

2.Rectal temperature

a.Rectal temperature was collected daily by the use of a digital rectal thermometer.

3.Skin temperature

a.Skin temperature was taken on day 0, day 2, 3 and 4 at the injection site by the use of an infrared thermometer, held 5cm above the skin.

4.Infrared eye temperature

a.Infrared eye images were taken of the left eye, at a distance of 45cm. This occurred each day (Day 0 – Day 4).

5.Tear staining

a.Tear staining occurred daily (Day 0 – day 4). It was obtained by taking a photograph of the left eye and measuring the area of tear staining via the use of the computer program ImageJ.

6.Behaviour

a.Behaviour was recorded by video camera between on day 0, day 1 and day 4, between 1pm and 5pm. Behaviour was assessed by the following ethogram.

BehaviourDescription

Lying (+contact) (d)Lying. In contact with other pen mates

Lying (-contact) (d)Lying. No pen mate contact

Sitting (d)Sitting, Weight distributed on front two feet and animals posterier

Standing (d)Standing. Weight distributed on all four feet

Running (d)Running around the pen

Walking (d)walking around the pen

Scratching (c)rubbing against or scratching inflammation area

Social given (c)Mounting pen mates, rubbing heads, nosing pen mate (touching any body part with nose, including belly nosing

Social receive (c)Receiving social behaviour and responding to it (note: if focal pig responds with reciprocal social behaviour then class as ‘social given’. If the behaviour lasted longer than 30 s, it was counted as two social interactions

Agonistic given (c)Aggressive behaviour towards another animal. Includes head thrusting with/without nites, ramming or pushing pen mates with head, fighting (mutual pushing or ramming  with or without biting in rapid succession; lifting the opponent by pushing the snout under its body), tail mouthing and biting. If the behaviour lasted longer than 30 s, it was counted as two agonistic interactions

Agonistic received (c)Receiving agonistic behaviour. it (note: if focal pig responds with reciprocal social behaviour then class as ‘agonistic given’

(d) – measured the duration of time, (c) counted the number of times this occurred

We should use a model based on the type of underlying distribution:  binomial for proportions  Poisson for counts  gamma or Weibull for event times