SCIE4401 data use in natural sciences solution
QUESTION 1
(i)The Department of Fisheries conducts a study wherein the number of breeding Blue Swimmer Crabs
is observed at 32 different beaches at 2012 and 2015, respectively. The research question is: whether the
number of breeding Blue Swimmer Crabs has changed between 2012 and 2015., the dependent variable is
continuous (the number of breeding Blue Swimmer Crabs), and the dependent variable is categorical with two
levels (year 2012 , year 2015). Therefore, the hypothese is couched in term of difference between means, two
independent-samples t-tests is appropriate, also Boxplot is the most appropriate plot for this data structure.
0
10000
20000
30000
40000
2012 2015
Year
Number of breeding Blue Swimmer Crabs
Figure 1: Variation in annual Number of breeding Blue Swimmer Crabs
The box plots shown above indicate that the mean of the number of breeding Blue Swimmer Crabs at 2015
has a larger mean than 2012, and the spreads of the two years are relatively the same(infered from mean and
IQR calculated below).
The mean for the number of breeding Blue Swimmer Crabs at 2012 is 17467.3125 and the mean for the
number of breeding Blue Swimmer Crabs at 2015 is 22768.0312.
(I.C. RS 3318)