Try to answer the following questions here:

• What is this question used for?
• What does this question assess?
• What does the student have to do?
• How is the question randomised?
• Are there any implementation details that editors should be aware of?

### History and Feedback

#### Checkpoint description

Describe what's changed since the last checkpoint.

#### Christian Lawson-Perfect2 years, 4 months ago

Saved a checkpoint:

I've split each part into a separate question.

#### Christian Lawson-Perfect2 years, 4 months ago

Gave some feedback: Should not be used

Published this.

#### Elliott Fletcher2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Elliott Fletcher2 years, 4 months ago

Gave some feedback: Has some problems

#### Aiden McCall2 years, 5 months ago

Question:

Needs a comma between outcomes and you. "For equally likely outcomes, you can..."

I would personally change 'happening' to 'occuring'.

I would also change 'So' to 'Therefore'.

Change 'Let's say' to 'If'.

The question with the example does seem quite wordy. I was wondering if you would be able to reduce the words by having a table for the line starting "We roll a...".

I don't think you need a comma after "fair" in "fair 6-sided die". I would then place the comma as follows, "fair 6-sided die, we are equally..."

I also don't think you need a comma after 'Hence'.

For c) I would add another answer with the same numerator but different denominator. This is because you do not have to calculate the probability but just look for the numerator with the same value as the blue balls. I understand that in the cases of simplification this may not be the case, but I think these occur less often then not.

a) i) "Now we must think how many outcomes are there that result in an even number being rolled." I would remove are there that so it reads as follows.
"Now we must think how many outcomes result in an even number being rolled.

c) "As the ball is being selected randomly from the bag, there is an equal probability of selecting a ball which is any of the 3 colours."

I am not sure this statement is true or at least reads such that, there is an equal probability of selecting any of the 3 colours when the probabilities for the selection of the three colours are different.

#### Elliott Fletcher2 years, 5 months ago

Gave some feedback: Needs to be tested

#### Chris Graham2 years, 5 months ago

As discussed, it would be nice to have an example in the statement.

#### Vicky Hall2 years, 5 months ago

Gave some feedback: Has some problems

#### Vicky Hall2 years, 5 months ago

Good intro to basic concepts. Part c) seems a little contrived though - there's no way I would let my daughter pick a pet at random! Also, the outcomes are probably not equally likely because the child probably doesn't like each type of pet equally, and within each group there are likely to be distinctions too. I would think of another example where it makes sense to be randomly assigned something or to randomly pick something. The numbers need to be variables and you should let the student know to simplify their answer.

#### Elliott Fletcher2 years, 5 months ago

Gave some feedback: Needs to be tested

#### Elliott Fletcher2 years, 5 months ago

Created this.
Basic Probability Questions Should not be used Elliott Fletcher 20/11/2019 14:33
Choose the probability of getting certain scores on a die Ready to use Christian Lawson-Perfect 20/11/2019 14:34
Probability of flipping a coin and getting a tails Ready to use Christian Lawson-Perfect 20/11/2019 14:41
Probability of picking a particular colour ball from a bag Ready to use Christian Lawson-Perfect 20/11/2019 14:41
Maria's copy of Choose the probability of getting certain scores on a die draft Maria Aneiros 27/05/2019 02:29
Maria's copy of Probability of picking a particular colour ball from a bag draft Maria Aneiros 27/05/2019 02:32
Choose the probability of getting certain scores on a die draft Xiaodan Leng 11/07/2019 01:57
Probability of flipping a coin and getting a tails draft Xiaodan Leng 11/07/2019 01:58
Probability of picking a particular colour ball from a bag draft Xiaodan Leng 11/07/2019 01:58

Give any introductory information the student needs.

No variables have been defined in this question.

(a number)

Numbers between and (inclusive) with step size
A random number between and (inclusive) with step size

(text string)

(numbers)

(text strings)

This variable is an HTML node. HTML nodes can not be relied upon to work correctly when resuming a session - for example, attached event callbacks will be lost, and mathematical notation will likely also break.

If this causes problems, try to create HTML nodes where you use them in content areas, instead of storing them in variables.

Describe what this variable represents, and list any assumptions made about its value.

This variable doesn't seem to be used anywhere.

Name Type Generated Value

#### Error in variable testing condition

There's an error in the condition you specified in the Variable testing tab. Variable values can't be generated until it's fixed.

Error:

for seconds

Running for ...

No parts have been defined in this question.

Select a part to edit.

The correct answer is an equation. Use the accuracy tab to generate variable values satisfying this equation so it can be marked accurately.

#### Checking accuracy

Define the range of points over which the student's answer will be compared with the correct answer, and the method used to compare them.

#### Variable value generators

Give expressions which produce values for each of the variables in the expected answer. Leave blank to pick a random value from the range defined above, following the inferred type of the variable.

#### String restrictions

Both choices and answers must be defined for this part.

Help with this part type

##### Base marking algorithm

#### Test that the marking algorithm works

Check that the marking algorithm works with different sets of variables and student answers using the interface below.

Create unit tests to save expected results and to document how the algorithm should work.

There's an error which means the marking algorithm can't run:

Name Value

Note
Value Feedback

Click on a note's name to show or hide it. Only shown notes will be included when you create a unit test.

#### Unit tests

No unit tests have been defined. Enter an answer above, select one or more notes, and click the "Create a unit test" button.

The following tests check that the question is behaving as desired.

### This test has not been run yet This test produces the expected output This test does not produce the expected output

This test is not currently producing the expected result. Fix the marking algorithm to produce the expected results detailed below or, if this test is out of date, update the test to accept the current values.

One or more notes in this test are no longer defined. If these notes are no longer needed, you should delete this test.

Name Value

 This note produces the expected output

This test has not yet been run.

When you need to change the way this part works beyond the available options, you can write JavaScript code to be executed at the times described below.

Run this script the built-in script.

This script runs after the built-in script.

To account for errors made by the student in earlier calculations, replace question variables with answers to earlier parts.

In order to create a variable replacement, you must define at least one variable and one other part.

The variable replacements you've chosen will cause the following variables to be regenerated each time the student submits an answer to this part:

These variables have some random elements, which means they're not guaranteed to have the same value each time the student submits an answer. You should define new variables to store the random elements, so that they remain the same each time this part is marked.

### Parts

Give a worked solution to the whole question.

### Preamble

This script will run after the question's variable have been generated but before the HTML is attached.
Apply styling rules to the question's content.

This question is used in the following exams: