# Upper bound or limit of the confidence interval

The superintendent of a unified school district of a small town wants to make sure that no more than 5% of the students skip more than 10 days of school in a year. A random sample of 145 students from a population of 800 showed that 12 students skipped more than 10 days of school last year. What is the upper bound or limit of the 95% confidence interval for the proportion of students who skipped more than 10 days of school last year

A) .1978

B) .1168

C) .1231

D) .1268

https://brainmass.com/statistics/confidence-interval/upper-bound-limit-confidence-interval-535177

#### Solution Preview

Upper bound will be given as

Sample Proportion (p) + 1.645*Sqrt(p*(1-p)/n)

= 12/145 + ...

#### Solution Summary

This solution is comprised of a detailed explanation for confidence interval for proportion using hand calculation to find out the correct answer. In this solution, step-by-step explanation of this complicated topic provides students with a clear perspective of 95% confidence interval for proportion with the help of calculations. Formulas are added in word file for better understanding and interpretation is given at the end of question.