Graphs And Shitt

Question 1

Quantitative data

Answer 1

Any number of possible values (eg. Weight)

Question 2

Qualitative data

Answer 2

Have only certain possible values (eg. Race)

Question 3

Discrete/continuous data

Answer 3

Information that only takes certain values

Usually numbers

Question 4

Non discrete/discontinuous data

Answer 4

X

Question 5

Difference between histograms and bar charts

Answer 5

Histograms have NO SPACES between bars

Question 6

What to look for when looking at histograms?

Answer 6

• is there more than one peak?
• overall shape? Is it symmetrical or skewed?
• is the shape wide or right? Range of the intervals the bars are plotted at?
• concentration of points or outliers that distort the graph?

Question 7

How to interpret box plot graphs?

Answer 7

X

Question 8

Boxplots with raw data

Answer 8

X

Question 9

What do box plots show?

Answer 9

Visual representation to show distribution of numerical data

5 number summary of the data (minimum, first quartile, median, third quartile and maximum)

Question 10

Dot plots

Answer 10

• alternative to a bar chart
• height of vertical bars indicated with a dot instead
• same interpretation as a bar chart

Question 11

Side by side box plots

XXX

Answer 11

• width of boxes can be made proportional to the number of values in each category
• do read the symmetry vertically ???? Ask Harv ???
• ## how does the symmetry of each box plot differ across categories?

Question 12

X

Answer 12

X

Question 13

Bar plots can also be presented as …

Answer 13

Stacked

Question 14

What is standard deviation used for?

Answer 14

To measure the range of values around a mean

Question 15

Does standard deviation have a degrees of freedom?

Answer 15

NO

Question 16

Standard deviation - YES overlap

Answer 16

There IS an overlap in the SD bars indicates there is NOT a significant difference and results are likely to be due to chance

Question 17

Standard deviation extra information

Check with Harv
XXXX

Answer 17

• smaller SD, the narrower the range = higher reproducibility
• smaller SD = experimental values clustered close together means higher precision

Question 18

Standard deviation equation

Answer 18

Square root

Of the sum of the difference of the squares/ (n-1)

Question 19

Standard deviation is the

Answer 19

Square root of variance

Question 20

What is variance in SD?

Answer 20

Average of the squared differences from the mean

Question 21

Explain in words how to calculate standard deviation?

Answer 21

1) calculate mean of all the values
2) subtract the mea from each value (to find how far each value is from the mean)
3) square the result for each number ^ (this is called the ‘squared difference’)
4) work out the average of the squares differences but adding all the values you get above and dividing by the total number of values measured

SD for population - divide by N (total number of values measured)

SD for sample of a population - divide by (N-1)

Question 22

What do you divide by when working out SD for a population compares to a sample ?

Answer 22

Population - N

Sample - N-1

Question 23

What actually are degrees of freedom?

???? Whatttt

Answer 23

Maximum number of logically independent values which are values that have the freedom to vary in a data sample

Question 24

What do we usually use as a critical value?

Answer 24

0.05 or 95%

Question 25

What actually is a p value ?

XXX

Answer 25

Probability of obtaining a result at least as extreme as the one that was actually observed in the biological experiment given that the null hypothesis is true

Question 26

When do we REJECT the null hypothesis (In terms of calculated and critical values)

Answer 26

If the calculated value exceeds the critical value then we REJECT the null hypothesis