According to a survey conducted by Lger on behalf of the Journal de Montral, COVID-19 has changed perceptions of Quebecers in several respects. Thus 60% (59% according to the survey of Quebecers believe that the use of public transit will decrease. The survey was carried out among 1,003 Quebecers. In admitting random sampling, the maximum margin of error is 3.1%, 19 times out of 20. These aspects of a survey are dealt with in a chapter subsequent. We randomly select 15 Quebecers who are able to use the public transport and we are interested in the number of Quebecers in the sample which considers that the use of public transport common will decrease.

b) Determine, using the property b(r; n, p) = b(n-x; n, 1-p), the probability that exactly 7 Quebecers in the sample considers that the use of public transport will decrease.