Apolitical candidate has asked you to conduct a poll to determine what percentage of people support her.
if the candidate only wants a 8% margin of error at a 95% confidence level, what size of sample is needed?

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?