In a survey of employees, Watson-Wyatt reported that 51% had confidence in the actions of senior management. 17 To be 95% confident that at least half of all employees have confidence in senior...

In a survey of employees, Watson-Wyatt reported that 51% had confidence in the actions of senior management.¹⁷
To be 95% confident that at least half of all employees have confidence in senior management, how many would have to be in the survey sample?

Fireman’s Fund commissioned an online survey of 1,154 wealthy homeowners to find out what they knew about their insurance coverage.

(a) When asked whether they knew the replacement value of their home, 63% replied yes. In this case, should Fireman’s Fund conclude that more than half of wealthy homeowners know the value of their homes?

(b) Round the interval into a form suitable for presentation.

(c) The results of the survey were accompanied by the statement, “In theory, with probability samples of this size, one could say with 95 percent certainty that the results have a statistical precision of plus or minus 3 percentage points. This online sample was not a probability sample.” What is the point of this comment?