Reference no: EM133207724
Assignment: How Temperature Affects the Survival of Sea Turtle Eggs
A. A biologist studies habitat use in black bears. The study area has 2300 acres of pine forest, 1500 acres of hardwood forest, and 350 acres of meadow. A black bear has a radio collar than tells the biologist its position at one randomly chosen time each day. Of the bear's positions recorded over the course of the summer the biologist finds that 27 positions are in pine forest, 89 positions are in hardwood forest, and 15 positions were located in meadow habitat. The biologist wants to determine if the bear is using the three habitat types proportionally-that is does the bear spend as much time in each of the three habitat types as would be predicted given the abundance of that habitat type. Below, calculate the expected values should the biologist use in a chi-square test that tests this null hypothesis.
1. Calculate expected counts and put them in this table (don't round to integers).
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Habitat
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Pine
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Hardwood
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Meadow
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Expected counts
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|
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|
2. What is the p value for your statistic test?
3. What is your conclusion about bears?
B. A researcher wants to know how the amount of REM sleep is influenced by exercise. The get 16 people and randomly assign them into two groups of eight. They then have one group engage in no exercise during one day and the other group engages in moderate exercise. That night they wire the people and determine how much time each individual spends in REM sleep. Below are the data collected?
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Individual
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Amount of REM sleep in hours
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no exercise
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moderate exercise
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1
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1.1
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3.5
|
|
2
|
0.6
|
2.1
|
|
3
|
0.4
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3.2
|
|
4
|
1.1
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1.0
|
|
5
|
2.3
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0.9
|
|
6
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1.2
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2.7
|
|
7
|
0.9
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2.1
|
|
8
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1.7
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3.2
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1. What kind of test should you run to determine if the two means differ from each other?
2. What was your p value?
3. What conclusion about REM sleep should the research draw from this research?
C. A biologist is interested in how temperature affects the survival of sea turtle eggs. They collect eggs and incubate them at two different temperatures (24 and 28 degrees C) and see how many survive to produce hatchlings (baby turtles) and how many die. Their data is as follows--at 24 degrees 120 eggs survive and 15 die. At 28 degrees 200 eggs survive and 8 die. Calculate the expected numbers you would need to the null hypothesis that temperature doesn't influence egg survival or mortality (put value in table below).
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Survived
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Died
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24 degrees
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|
|
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28 degrees
|
|
|
1. What is your p value?
2. What is your conclusion about sea turtle eggs?
D. A researcher has 16 mice from a highly inbreed strain of mouse. The put each in a separate cage and then feed half of them (randomly chosen) Purina mouse food and the other half of them Purina rat food. The units for the means are growth rates in units of mg per day. What test should you run to determine if mean growth rate differs on the two diets? What was your calculated t and p values? What should you conclude?
|
Mouse food
|
11.2
|
10.3
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11.4
|
12.4
|
12.5
|
11.6
|
11.2
|
10.9
|
|
Rat food
|
9.7
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9.0
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8.8
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8.1
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10.5
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9.4
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8.9
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8.1
|
E. A biologist wants to determine if typical male body weight is the same for males and females in a species of bird. They get a male and a female chick from seven different nests and grow them up to adult size. The adult weights in grams for the birds are below:
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|
Nest1
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Nest2
|
Nest3
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Nest4
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Nest5
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Nest6
|
Nest7
|
|
Female
|
5.8
|
6.2
|
5.4
|
5.5
|
6.6
|
5.2
|
6.1
|
|
Male
|
5.7
|
6.0
|
5.1
|
5.5
|
6.4
|
4.9
|
6.1
|
1. What test would you use to determine male and female body weights differ significantly in these populations?
2. What is the calculated value for the test statistic for this test and what is the p value?
3. What is your conclusion?