Flashcards in Maths Deck (19):

1

## Percentage error =

###
Uncertainty

-------------- X 100

Reading

2

## Uncertainty value?

### Half the smallest graduation e.g. on a ruler with 1mm graduations it would be 0.5mm

3

## Margin of error?

### Uncertainty value double e.g. On a ruler with 1mm graduations the margin of error would be 1mm

4

## Sampling bias?

### You unintentionally avoid areas of your potential sample e.g. Muddy areas.

5

## Chance?

### Even without bias it may not have been representative as it is impossible to test every single thing.

6

## Why won't things be representative?

###
- sampling bias

- chance

7

## Ways to avoid sampling bias?

###
- random sampling e.g. Random coordinates.

- using a larger sample, less chance of chance effect the results.

- analysis of data collected e.g. Stats tests, mode, median, mean and standard deviation.

8

## Standard deviation?

### Measuring variation from the mean in a sample. Smaller standard deviations results more clustered data which means less extreme values so it is more reliable. Standard deviation is a good measure of the reliability of the mean.

9

## Normal distributions of standard deviation?

### Standard deviation valve is smaller for A than B so the smaller the spread of data around mean A which is therefore a more reliable mean.

10

## Binomial distribution, comparing two standard deviations?

### Standard deviation value for A is smaller than B so smaller spread of data around mean A which is therefore a more reliable mean. No overlap between standard deviations means there is a significant difference between the two means.

11

## Rate of reaction =

###
Y

----

X

12

## Chi squared?

###
Null hypothesis: no significant difference in NUMBER

Appropriate table: normal two headed table

How to present data: bar chart

13

## Student T test?

###
Null hypothesis: no significant difference in MEAN

Appropriate table: table with mean column

How to present data: bar chart with standard deviation bars

14

## Spearmans Rank?

###
Null hypothesis: no significant difference in CORRELATION

Appropriate table: pairs of data in table

How to present data: scatter gram

15

## At p = 0.01 to p = 0.05

### Reject the null and accept the experimental as there is a significant difference

16

## At p = 0.06 and above

### Accept the null hypothesis and reject the experimental hypothesis as there is not a significant difference

17

## What are the three stats tests?

### Chi squared , student t test and spearmans rank.

18

## Volume of solute needed =

###
Concentration you want

------------------------------- X total volume you want

Concentration you've got

19