Transcript Statistics - University of Miami

Natalia Rodriguez
Research in Ecology
Average Length of Sharp-nose Sharks
Males
998
Gender of Shark
Female
Male
Female
952
Male
920
940
960
980
1000
Average Length of Sharks
The Mean is the average. To find the mean
you add up all the numbers and divide it by
the total amount of numbers. Female sharks
are much larger than males.
Females
920
928
935
943
950
950
954
960
962
974
975
975
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
1160
Number of Sea Turtle Hatchlings in
Beach Site A
25
25
25
25
25
Number of SeaTurtles
25
20
15
15
11
10
10
3
5
0
0
Blue
Yellow
Green
Color Groups
Red
Orange
Very few sea turtles make it to the
ocean each year. They face many
dangers such as pollution, preadators
(racoons, dogs, gulls…), misleading
lights and poachers.
Color
Survived
#Hatchlings
Blue
11
25
Yellow
3
25
Green
0
25
Red
Orange
10
15
25
25
Percentage of Bottle Cap Colors
10%
Red
14%
Orange
5%
22%
Yellow
Blue
12%
Green
Black
11%
14%
12%
White
Clear
Percentage
is the
amount in
each
hundred like
a fraction
10/100.
Bottle caps are a big
problem for the ocean.
Many animals eat them or
make homes in them. Bottle
caps are one of the most
commonly found beach
trash along with plastic
bags.
Frequency Distribution of Sea
Cigars By Size (cm)
12
12
Frequency
10
8
5
6
4
3
4
2
1
0
0
"1-5"
"6-10"
"11-15"
"16-20"
Size Class (cm)
"21-25"
"26-30"
Red mangroves are more
important than people think. Their
prop roots provide a small
ecosystem that protects small fish
and other marine animals from
predators. Animals that live here
are snowy egret, white ibis, brown
pelican, cormorants, mangrove
cuckoos, herons, manatees,
monkeys, turtles, red-tailed hawks,
sea turtles, American alligators and
crocodiles, and mangrove tree
crabs…
Trial
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Water
Temp
2
3
1
2
6
4
3
6
2
4
3
1
1
3
4
1
2
2
Depth
1
4
1
1
2
4
5
1
3
1
6
6
3
6
1
3
4
4
Wave
Action
4
3
1
2
1
1
1
5
2
6
1
1
2
3
4
6
5
6
Survived?
Y
N
N
N
N
N
N
N
N
Y
N
N
N
N
Y
N
Y
Y
Probability of Coral Survival
0.3
0.25
Probability
Probability is a way to
measure the chances that
something will occur in relation
to the possible alternatives.
0.27
0.22
0.2
0.15
0.1
0.05
0
Theoretical Probability
Observed Probability
Types
To survive a coral needs warm water,
shallow water, and rough waves. The
color from the coral comes from little
algae that lives inside the coral. When
the algae dies due to global warming
the coral kicks it out and loses its color.
Wave action killed the coral the most.
• Variance is a way to show how far
away your data is from the mean.
• Variance is calculated with this formula:
2
𝑠 =
𝑋−𝑋
𝑛 1
2
∑= sum X= the mean of data X= each data value n=the number of values
• Variance is also symbolized by the
Greek letter sigma squared δ2
• Standard Deviation (δ) describes how
spread out the data are.
• Standard deviation is the square root of
the variance.
δ= 𝛿2
• One standard deviation is considered the
numerical distance away from the mean in
the positive or negative direction.
• We say plus or minus some number away
from the mean.
Actual Distribution of Sea Cigars by
Length
Theoretical Distribution of Sea Cigars
by Length
3
4
2.5
Frequency
Frequency
3
2
1
2
1.5
1
0.5
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Length (cm)
0
0
2
4
6
Length (cm)
A Theoretical Distribution
Curve (TDC) is an ideal picture
of a distribution based upon
random sampling.
8
10
T-Tests are used to test if there is
a significant difference between
the data.
It’s calculated with this
formula:
P
𝑋1 𝑋2 = 𝑚𝑒𝑎𝑛s of
samples 1 and 2
𝑆𝑝2 = pooled variance
𝑛1 𝑛2 = number of
objects in each group
IF the calculated t-statistic is
larger than the one from the
table, the null hypothesis is
rejected.
IF the calculated t-statistic is
less than the one from the
table you fail to reject the null
hypothesis.
Control
14
13
13
13
13
13
Treatment
14
13
15
15
15
14
14
14
15
15
P= 0.000545