Question 1

Which of the following best describes the difference between quantitative and qualitative data?

Accepted Answer

Quantitative data can be measured numerically and calculations can be performed on them, while qualitative data represent categories or labels without numerical meaning.

Question 2

A researcher records the number of goals scored by each player in a soccer tournament. What type of data is this, and what is the most appropriate measurement scale?

Accepted Answer

Quantitative, discrete; ratio scale

Question 3

Which of the following is an example of a variable measured on an ordinal scale?

Accepted Answer

Customer satisfaction rated as 'Very dissatisfied', 'Dissatisfied', 'Neutral', 'Satisfied', 'Very satisfied'

Question 4

A company wants to estimate the average salary of its employees. They divide employees into departments and randomly select a few employees from each department. Which sampling method is being used?

Accepted Answer

Stratified sampling

Question 5

Which of the following statements about simple random sampling is TRUE?

Accepted Answer

Each group of n cases has an equal chance of making up the sample.

Question 6

A frequency distribution for a categorical variable shows:

Accepted Answer

The number of observations in each nonoverlapping category.

Question 7

Which graphical method is most appropriate for summarising the distribution of a quantitative variable?

Accepted Answer

Histogram

Question 8

Given the following audit times (in days): 12, 14, 19, 18, 15, 15, 18, 17, 20, 27, 22, 23, 22, 21, 33, 28, 14, 18, 16, 13. Using Sturge’s rule, what is the approximate number of classes for a frequency distribution?

Accepted Answer

$$1 + 3.3 \log(20) \approx 5$$

Question 9

In a cumulative frequency distribution, what does the cumulative frequency for a class represent?

Accepted Answer

The number of data points with values less than or equal to the upper class limit of that class.

Question 10

A bar chart is used to display the frequency of soft drink purchases. Which axis should display the categories of soft drinks?

Accepted Answer

x-axis (horizontal axis)

Question 11

Which of the following is a key difference between stratified sampling and cluster sampling?

Accepted Answer

Stratified sampling samples from every subgroup, while cluster sampling samples entire clusters.

Question 12

A stem-and-leaf display is particularly useful because:

Accepted Answer

It shows both the raw data and the shape of the distribution.

Question 13

Which of the following is an example of time series data?

Accepted Answer

Monthly exchange rates of the South African Rand to the US Dollar over a year.

Question 14

If a sample is not representative of the population, what is the most likely consequence?

Accepted Answer

The results may be biased and not generalizable to the population.

Question 15

Which of the following best describes a cross-tabulation?

Accepted Answer

A tabular summary of data for two variables, showing the frequency of each combination of categories.

Question 16

A researcher wants to select every 10th person from a list of 1,000 people. What sampling method is this?

Accepted Answer

Systematic sampling

Question 17

Which of the following is NOT a property of a nominal scale?

Accepted Answer

The order of the categories is meaningful.

Question 18

In the context of the research process, what is the main purpose of descriptive statistics?

Accepted Answer

To summarise and present data in a form that is easy to understand.

Question 19

Which of the following is an example of a sampling error?

Accepted Answer

The sample mean differs from the population mean due to random selection.

Question 20

Which of the following best describes a representative sample?

Accepted Answer

A sample that mirrors every characteristic of the population.

STK110 Study Notes: Data, Statistics, and Sampling

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