Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Unit 1: Statistical Analysis > Flashcards

Unit 1: Statistical Analysis Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
0
Q

What factors determine the number of samples in an experiment?

A

Time, money, and people available to do the science

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What does observation result in?

A

The collection of measurable data

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do samples represent in an experiment?

A

The entire population of the sampled thing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is statistics?

A

A branch of mathematics which allows us to sample small portions from habitats, communities, or biological populations, and draw conclusions about the larger population by mathematically measuring the differences and relationships between sets of data.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the mean?

A

The average of the data points; the central tendency of the data

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the range?

A

Calculating the difference between the largest and smallest observed values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are outliers?

A

Unusually large or small data points that would have a great effect on the range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is standard deviation?

A

A measure of how the individual observations of a data set are dispersed or spread around the mean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the abbreviation for standard deviation?

A

SD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are error bars?

A

A graphical representation of the variability of the data

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What can error bars be used to show?

A

Either the range of data or the standard deviation on a graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do we use standard deviation to do?

A

To summarise the spread of values around the mean and to compare the means and spread of data between 2 or more samples

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What percent of all values lie within +/- 1 standard deviation of the mean in normal distribution?

A

68%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What percent of all values lie within +/- 2 standard deviations from the mean in normal distribution?

A

95%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What size is the standard deviation when the data points are clustered together?

A

Small

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What size is the standard deviation when the data points are spread apart?

A

Large

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the shape of a graph of normal distribution?

A

Bell curve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If the bell curve is flatter, what size would the standard deviation be?

A

Large

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

If the bell curve is taller and thinner, what size would the standard deviation be?

A

Small

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why is standard deviation showing the spread of data around the mean useful?

A

It tells you how many extremes are in the data

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

If there are many extremes in the data, what size will the standard deviation be?

A

Large

21
Q

If there are few extremes in the data, what size will the standard deviation be?

A

Small

22
Q

How is the standard deviation useful for comparing the means of two or more sets of data?

A

When comparing two sets of data which have exactly the same mean, we must also look at the standard deviation, because if the standard deviation of one data set is much higher than the other, it indicates a very wide spread of data around the mean for that data set; this makes us question the experimental design that is cause this wide variation in the data

23
Q

Why is it important to calculate the standard deviation in addition to the mean of a data set?

A

If we looked only at the mean, we would not see that one data set may be more variable than the other

24
Q

What is the t-test commonly used to determine?

A

Whether or not the difference between two sets of data is a significant (real) difference

25
Q

What is “p” in a t-test?

A

Probability that chance alone could produce the difference

26
Q

What is the probability that the difference is due to chance if p=0.05? Is it significant?

A

5%, yes

27
Q

What does it mean if p=0.5?

A

There is a 95% chance that the difference is due to the independent variable and not chance

28
Q

What percentage chance is significant in statistics?

A

95%

29
Q

Even though statisticians are never completely certain, they like to be at least what percent that their findings are significant and not due to chance before drawing conclusions?

A

95%

30
Q

What is used to calculate the value of “t”?

A

Mean, standard deviation, and sample size

31
Q

How do you find the degrees of freedom?

A

Find the sum of the sample sizes of each of the two groups, then subtract 2

32
Q

How do you find “p” when given a calculated value of “t” and a table of “t” values?

A

Find the degrees of freedom, then look in the left-hand column headed “degrees of freedom” and then across to the given t value; find the p value at the bottom of the column for the given t value

33
Q

What do experiments provide?

A

A test which shows cause (causation)

34
Q

What can observations without an experiment only show?

A

A correlation

35
Q

Correlation does not mean what?

A

Causation

36
Q

What story includes an interesting correlation example?

A

Africanized honey bees (AHBs) invading the USA

37
Q

When and where were Africanised honey bees discovered in the US?

A

In 1990, outside a small town in Texas

38
Q

How did AHBs come to the Americas?

A

They were brought from Africa to Brazil in the 1950s I. The hope of breeding a bee adapted to the South American tropical climate, but by 1990, they had spread to the southern US

39
Q

What did scientists predict would happen if AHBs came into the US?

A

They would invade all the southern states of the US, but this hasn’t happened

40
Q

Where have the AHBs remained?

A

In the southwest states of the US

41
Q

What point coincides with get area around the areas where the AHBs have remained?

A

That there’s an annual rainfall of 137.5 cm (55 inches) spread evenly throughout the year

42
Q

What seems to be a barrier to the movement of the AHBs and why?

A

The level of year-round wetness from even rainfall throughout the year, because the AHBs do not move into such areas

43
Q

What does the value of “r” signify when using a mathematical correlation test?

A

The correlation

44
Q

What does an r-value of +1 show?

A

A completely positive correlation

45
Q

What does an r-value of 0 show?

A

No correlation

46
Q

What does an r-value of -1 show?

A

A completely negative correlation

47
Q

What is required to find the cause of observed correlation?

A

Experimental evidence

48
Q

Even if there is a high correlation, only carefully designed experiments can do what?

A

Separate causation from correlation

49
Q

What does the null hypothesis state?

A

The difference observed is due to chance and therefore is not significant

Biology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions