a The data are unlikely to be reliable.

b Your judgement should be based on a combination of the following reasons:

• Initial examination of the report reveals that it is an internally conducted survey. As this has been undertaken by the marketing department of a large manufacturing company, you might assume that those undertaking the research had considerable expertise. Consequently, you might conclude the report contains credible data.

However:

• The methodology is not clearly described. In particular:

• The sampling procedure and associated sampling errors are not given.

• It does not appear to contain a copy of the questionnaire. This means that it is impossible to check for bias in the way that questions were worded.

• The methodology for the qualitative in-depth interviews is not described.

• In addition, the information provided in the methodology suggests that the data may be unreliable:

• The reported response rate of 12.5 per cent is very low for a telephone survey

( Section 7.2 ).

• Responses from 25 people means that all tables and statistical analyses in the report are based on a maximum of 25 people. This may be too few for reliable results

( Sections 7.2 and 12.5 ).