Practcal Skills - IMPORTANT

Question 1

Precision is reduced by ______ ______ . Precise results do not ______ ______ ______ ______ ______

Answer 1

random error / vary much from the mean

Question 2

Repeatable means, if the same person repeats the experiment using the same ______ and ______ , they will get the ______ ______ .

Reproducible means if ______ ______ does the experiment,using a ______ ______ ______ or ______ ______ ______ the results will be ______ ______ .

Answer 2

methods / equipment / same results

soomeone different / slightly different method / piece of equipment / the same

Question 3

To get valid results, you need to ______ _______ ______ ______ .

Answer 3

control all the variables

Question 4

How could you increase the accuracy of your results?

Answer 4

Use a larger sample size.

Question 5

The variable you change is called the ______ variable.

The variable that you measure is called the ______ variable.

Answer 5

independent

dependent

Question 6

Why would you use a negative control?

What would you expect their effect to be?

Answer 6

To check that only the independent variable is affecting the dependent variable.

They should have no effect on the experiment.

Question 7

How would you reduce the effect of random error?

Answer 7

By repeating the experiment at least three times and by calculating a mean.

Question 8

How do you increase precision?

Answer 8

Use more sensitive and accurate apparatus/equipment.

Question 9

Quantitative data = ?

Discrete data = ?

Continuous data = ?

Qualitative data = ?

Answer 9

numerical

certain value within a range (shoe size)

any value within a range (height / weight)

categorical

Question 10

How do you find the rate using a graph?

Answer 10

Question 11

Uncertainty is the amount of ______ your ______ might have.

You can calculate it using what formula?

Answer 11

error / measurement

Percentage error = uncertainty x 100
reading