<p>One question in a survey is as follows:<br>“Do you use Facebook during office hours at least once a day? Yes or No?''<br>It is known that on average, \(7\) out of \(9\) staff members answered “yes” to the above question. For the random sample of \(60\) staff members selected,</p>
<ol class="i-list"><li><div class="list-item-content"><span class="list-item-text">find the standard deviation of the number of staff members who answer “yes”,</span><span class="inline-marks">[1]</span></div></li><li><div class="list-item-content"><span class="list-item-text">find the probability that the number of staff members who answer “yes” exceeds the mean,</span><span class="inline-marks">[3]</span></div></li><li><div class="list-item-content"><span class="list-item-text">find the most probable number of staff members who answer “yes”,</span><span class="inline-marks">[2]</span></div></li></ol>

One question in a survey is as follows:
“Do you use Facebook during office hours at least once a day? Yes or No?''
It is known that on average, \(7\) out of \(9\) staff members answered “yes” to the above question. For the random sample of \(60\) staff members selected,

find the standard deviation of the number of staff members who answer “yes”,

find the probability that the number of staff members who answer “yes” exceeds the mean,

2013 DHS P2 Q10

2013 DHS P2 Q10