Maths

Question 1

Percentage error =

Answer 1

Uncertainty
————– X 100
Reading

Question 2

Uncertainty value?

Answer 2

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

Question 3

Margin of error?

Answer 3

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

Question 4

Sampling bias?

Answer 4

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

Question 5

Chance?

Answer 5

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

Question 6

Why won’t things be representative?

Answer 6

• sampling bias

- chance

Question 7

Ways to avoid sampling bias?

Answer 7

• 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.

Question 8

Standard deviation?

Answer 8

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.

Question 9

Normal distributions of standard deviation?

Answer 9

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.

Question 10

Binomial distribution, comparing two standard deviations?

Answer 10

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.

Question 11

Rate of reaction =

Answer 11

X

Question 12

Chi squared?

Answer 12

Null hypothesis: no significant difference in NUMBER
Appropriate table: normal two headed table
How to present data: bar chart

Question 13

Student T test?

Answer 13

Null hypothesis: no significant difference in MEAN
Appropriate table: table with mean column
How to present data: bar chart with standard deviation bars

Question 14

Spearmans Rank?

Answer 14

Null hypothesis: no significant difference in CORRELATION
Appropriate table: pairs of data in table
How to present data: scatter gram

Question 15

At p = 0.01 to p = 0.05

Answer 15

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

Question 16

At p = 0.06 and above

Answer 16

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

Question 17

What are the three stats tests?

Answer 17

Chi squared , student t test and spearmans rank.

Question 18

Volume of solute needed =

Answer 18

Concentration you want
——————————- X total volume you want
Concentration you’ve got

Question 19

Magnification =

Answer 19

Actual size

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