stats + scientific method Flashcards

1
Q

what is discovery science

A

describing nature
qualitative data
observations

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2
Q

what is hypothesis-based science

A

explaining nature
quantitative data
experiments

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3
Q

steps of scientific method

A
  1. make observations
  2. ask questions
  3. form a hypothesis
  4. make a prediction
  5. test prediction
  6. interpret data
  7. draw conclusions
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4
Q

what does testing the prediction involve

A

plan experiments
perform experiments
collect data and analyze

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5
Q

what is a theory

A

well-substantiated explanation for a set of verified hypotheses

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6
Q

what is an independent variable

A

variable that is being manipulated
location

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7
Q

what is a dependent variable

A

results from the change to the independent variable
presence of mutations

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8
Q

what are the types of statistics

A

descriptive and inferential

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9
Q

what are descriptive stats

A

central tendency
measure of variance

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10
Q

what is central tendency

A

mode mean and median

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11
Q

what is the mode

A

most common number in a set of numbers

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12
Q

what is the median

A

the middle value in a set of numbers

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13
Q

what are the measures of variance

A

variance and standard deviation

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14
Q

what are inferential stats

A

error bar analysis
unpaired/independent t test

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15
Q

what are the characteristics of a normal distribution

A

all central tendencies are the equal
bell shaped curve
most of the values and in the middle
curve is symmetrical

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16
Q

what happens when the mean is standardized to zero

A

majority of points will be grouped in the middle

17
Q

what is variance

A

relative distance between data points and mean
S^2

18
Q

what is standard deviation

A

how far apart are the numbers in the sample
SD

19
Q

what is the main advantage of using standard deviation compared to variance

A

standard deviation is in the same units as the data points

20
Q

what is standard error

A

how accurate your results are compared to the population
SE

21
Q

what does having a higher S^2, SD or SE mean

A

there is more variability in the sample and we can be less confident in the results

22
Q

n < 10, gap is 2

A

likely significant, p is around 0.05

23
Q

n > 10, gap is 2

A

significant, p is around 0.01

24
Q

n > 10, gap is greater than 2

A

significant, p < 0.05

25
n > 10, gap is 1
likely significant, p around 0.05
26
n < 10, gap is greater than 2
significant, p < 0.05
27
n < 10, gap is 1
not significant, p > 0.05
28
gap is 0
not significant
29
when can you not use an unpaired t test
before and after of the same group no means comparing more than two groups or only one
30
t test steps
1. state hypotheses 2. write down data 3. write number of replicates 4. calculate means 5. calculate variance 6. calculate standard deviation 7. calculate t value 8. pick a significant value (0.05) 9. figure out if hypothesis is one or two tailed 10. find t critical 11. compare values
31
p value > alpha
no significance
32
alpha > p value
significant
33
how does the hypothesis being two tailed affect the alpha value
alpha becomes 0.025 for each side
34
t crit < t cal, negative one tailed
not significant
35
t crit > t cal, positive one tailed
not significant
36
t crit < t cal, positive one tailed
significant
37
t crit > t cal, negative one tailed
significant
38
t crit > t cal, two tailed
significant
39
t crit < t cal, two tailed
significant