Practice with these exercises to prepare for your seminars and wider research.

1. Outline the steps involved in drawing up the following types of sample:
(a) Simple random sample
(b) Stratified sample
(c) Cluster sample
(d) Multi-stage cluster sample
(e) Quota sample
(f) Snowball sample
(g) Volunteer sample
(h) Maximum variation sample
(i) Theoretical sample

2. What is the difference between probability and non-probability sampling? When is each approach useful?

3. Pick one or more of the sampling frames listed below. Discuss the adequacy of these lists in covering the populations concerned.
(a) What omissions are there likely to be?
(b) What problems of access might there be in getting these lists, and in approaching people listed on them?
(c) What stratifying factors are likely to be present and useful for each sampling frame?

Sampling frames

• Covering the general population: Register of electors; telephone directory; birth certificates; death certificates; postcode address file.
• Covering institutions: Directory of universities, schools or colleges; health services directory; directory of penal institutions.
• Covering professional groups: Medical directory; registers of psychologists, nurses, osteopaths; register of chartered surveyors; charities register.
• Some other groups: A university department’s list of students attending a course; hospital admissions daily log book; a school register of pupils or students; an employer’s records of employees; a solicitor’s records of clients.

4. Imagine that you are engaged in a small-scale interviewing survey, designed to discover how people feel about balancing the demands of home life with those of their work life. You have the resources to interview about 20 people.
(a) How would you select people to interview?
(b) How would you decide whether 20 was enough?

5. Design a sampling strategy, and estimate the likely sample size needed, that would answer the following research questions:
(a) What is the prevalence of poverty in the UK?
(b) How do school pupils approach their homework?
(c) What needle-sharing practices occur between injecting drug users?
(d) Does socio-economic status influence the types of crimes people commit?
(e) How has the public image of politicians changed over the past 20 years?
(f) What causes some small business start-ups to fail?
(g) What are the characteristics of women’s football fans?