 11.01 Random sampling

Interactive practice questions

Beth is interested in which students from her school catch public transport. Select whether the following sampling methods are likely to be biased or not.

a

Selecting every $10$10th person on the bus she catches.

Biased

A

Not biased

B

Biased

A

Not biased

B
b

Selecting every $10$10th person on the student list.

Biased

A

Not biased

B

Biased

A

Not biased

B
c

Selecting the first $50$50 students that arrive in the morning.

Biased

A

Not biased

B

Biased

A

Not biased

B
d

Selecting by having a computer randomly choose student numbers.

Biased

A

Not biased

B

Biased

A

Not biased

B
Medium
Less than a minute

Georgia wants to know how the people in Australia are going to vote in an upcoming referendum. She selects $50$50 random people from her city to interview.

Why might this sampling give poor results? Select all that apply.

Justin wants to know how the students at his school might vote for the next school captain. He leaves three flyers in each class to complete by whatever students want to complete them.

Why might this sampling give poor results?

Four lucky people from a group of $215$215 each stand to win an iPad. Every contestant is given a different number between $1$1 and $215$215, and the winners are selected by generating a random number uniformly between $0$0 and $1$1.

To ensure there is an equal chance of each contestant winning, the number is multiplied by $215$215 and then rounded up. In this case the numbers generated were:

 $0.152$0.152 $0.534$0.534 $0.352$0.352 $0.795$0.795

Outcomes

S-IC.1

Understand statistics as a process for making inferences to be made about population parameters based on a random sample from that population.

S-IC.3

Recognize the purposes of and differences among sample surveys, experiments, and observational studies; explain how randomization relates to each.