New Zealand
Level 7 - NCEA Level 2

# Sources of Errors

## Interactive practice questions

Tina wants to know which new smart phone she should buy and decides to base her decision on other people’s opinions. She decides to interview some people at the Retirement Home where her grandparents live one Sunday afternoon.

a

Is this an example of Sampling Error or Measurement Error?

Sampling error

A

Measurement error

B

Sampling error

A

Measurement error

B
b

What type of Sampling Error is this?

The sample is too small

A

The sample is not random

B

The sample does not adequately represent the population.

C

The sample is too small

A

The sample is not random

B

The sample does not adequately represent the population.

C
Easy
Less than a minute

An online store sent a survey to all people who had bought the recent book in the Harry Potter series and asked them “Which do you prefer, the Harry Potter Books or the Harry Potter Films?”

In order to determine the most common non-English language spoken in Melbourne, adults and children at a football game were asked: “Other than English, what language do you speak at home?”

Parents with young children enrolled at Pebbles Daycare centres around Australia were surveyed and asked the following question:

“Which is better? Private Schools or Public Schools?”

### Outcomes

#### S7-1

Carry out investigations of phenomena, using the statistical enquiry cycle: A conducting surveys that require random sampling techniques, conducting experiments, and using existing data sets B evaluating the choice of measures for variables and the sampling and data collection methods used C using relevant contextual knowledge, exploratory data analysis, and statistical inference.

#### S7-3

S7-3 Evaluate statistically based reports: A interpreting risk and relative risk B identifying sampling and possible non-sampling errors in surveys, including polls

#### 91265

Conduct an experiment to investigate a situation using statistical methods

#### 91266

Evaluate a statistically based report