91影视

800 people were interviewed by phone; 21% said they had used cocaine. Another 800 people were asked the question in a one-on-one personal interview; 25% said 鈥淵es.鈥� The remaining 800 were allowed to make an anonymous written response; 28% said 鈥淵es.鈥�

The two way response table (observed) for the given data is:

The two-way expected table for the given data is:

Since each of the frequencies are greater than 5, therefore we can apply ${饾搂}^2$test.

We have,

role="math" localid="1653900006347" ${饾潓}^2=\underset{i}{鈭�}\frac{{\left(O_i-E_i\right)}^2}{E_i}$

Upon substitution we get:

${饾潓}^2=\frac{{\left(162-195.3333\right)}^2}{195.3333}+\frac{{\left(200-195.3333\right)}^2}{195.3333}+\frac{{\left(224-195.3333\right)}^2}{195.3333}+\frac{{\left(638-604.6667\right)}^2}{604.6667}+\frac{{\left(600-604.6667\right)}^2}{604.6667}+\frac{{\left(576-604.6667\right)}^2}{604.6667}$

${饾潓}^2鈮�13.2395$.

The p-value can be calculated using the calculator is:

$p-value鈮�0.001334.$

Since $p-value鈮�0.001334>饾浖\left(=0.05\right)$, we reject $H_0$under the favor of $H_1$.