Answer to Question #263078 in Statistics and Probability for james

Question

Differentiate between probability sampling and non-probability sampling.

(2 marks)

b. Give any three reasons for sampling over a census. (3 marks)

c. Plot a scatterplot with at least 5 data point, given that the correlation

coefficient r = −1. (2 marks)

d. Differentiate between parametric and non-parametric tests. (2 marks)

e. The table below shows a relationship between the number of times an

advertisement was aired and digital camera sales. Use sales as the dependent

variable. Draw a scatter diagram. (2 marks)

Number of Airing Sales “000”

4 15

2 8

5 21

6 24

3 17

f. If a company employs 3500 people and if a random sample of 175 of these

employees has been taken by systematic sampling, what is the value of k?

(2 marks)

g. How does sampling error occur? (2 marks)

Answer 1

a

b.

Reduces costs, both monetary and in terms of manpower requirements.

Because it involves a lower scale of activity, it reduces the time required to gather, process, and generate data.

c.

d.

Parametric tests are those that make assumptions about the population distribution characteristics from which the sample is obtained. The assumption here is that the population data are regularly distributed. Non-parametric tests are "distribution-free," and so may be applied to non-Normal variables.

e

f

3500/175 =20 so k =20. The researcher would start the study somewhere between 1 and 20, which he could determine from a random number table.

The frame for the study could be obtained from the company's human resources department, which presumably has a list of all employees.

g

A sampling mistake happens when the study's sample is not representative of the entire population. By increasing the sample size, the prevalence of sampling mistakes can be minimized. Random sampling is another method for reducing the frequency of sampling mistakes.