Transcript Statistics for research in ecology

Christopher Contreras
Average length of sharp - nose sharks
1000
990
980
L
e
n
g
t
h
970
960
(
c
m
950
)
940
930
920
MALE
FEMALE
Gender of shark
Survival Rate of Hatchlings
NUmber of sea turtles
25
20
15
10
survived
started
5
0
blue
started
green
yellow
color players
survived
orange
red
Percentage of Bottle caps colors
clear
8%
other
4%
red
22%
white
26%
orange
7%
yellow
2%
blue
14%
black
12%
green
4%
purple
1%
Sea cigar count
14
12
10
8
# of sea cigar
"1-5"
"6-10"
6
"11-15
"16-20"
4
"21-25"
"26-30"
2
0
"1-5"
"6-10"
"11-15
"16-20"
Size intervals (in cm)
"21-25"
"26-30"
Variance is a value is used in statistics to
describe how far away your data is from
the mean. The mean is the average of the
data. The formula for the variance is
For example both sets of the following data have a
mean of 10. Set 1 : 8,9,10,11,12
Set 2: 1,2,10,17,20. In the first set there is not much
variation but in the second set the numbers vary a
lot.
Theoretical Distribution of 25 Sea
Cigar Lenghts
3
2.5
Frequency
2
1.5
B
1
0.5
0
0
5
10
15
Lenght of Sea Cigars (cm)
20
25
A Theoretical
Distribution Curve is
a theoretical or ideal
picture of a
distribution based
upon random
sampling.
The t-test is used to figure out if
there is a significant
difference between the
averages of two independent
samples of whatever they may
be. The t-test result is when its
greater than the number in
the 1-2 table you reject your
null hypothesis if it is less than
the number you accept the
null hypothesis. It
incorporates the mean, the
number and the variance.
The chi square test
can be used to see
if there are any
significant
differences
between data sites
or sources. We
played the sea
turtle game to see
the differences in
survival rates of
turtles on the
different nesting
sites.
Sea turtles are an endangered species and for
them to get to the sea and survive it is very
rare. There are many reasons why they die;
some of them can get eaten by predators
before they even hatch, some humans catch
them for different reasons, the get mislead by
city light into the city, or get run over by dune
buggies or other vehicles.