18 It is known from previous data that 14\% of the visitors to a particular cookery website are under 30 years of age.
To encourage more visitors under 30 years of age a large advertising campaign took place to target this age group.
To test whether the campaign was effective, a sample of 60 visitors to the website was selected. It was found that 15 of the visitors were under 30 years of age.
18
- Explain why a one-tailed hypothesis test should be used to decide whether the sample provides evidence that the campaign was effective.
18
- Carry out the hypothesis test at the \(5 \%\) level of significance to investigate whether the sample provides evidence that the proportion of visitors under 30 years of age has increased.
18 - State one necessary assumption about the sample for the distribution used in part (b) to be valid.
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