- It has been found that a certain proportion of
companies listed in the Stock Exchange report higher profits than
what they actually make. An audit of 200 companies’ accounts showed
that 30 companies reported incorrect higher profits.
- Identify the variable of interest – be specific in a complete
sentence (3pts)
- Calculate the statistic for this sample. Also
calculate the standard error to be used in a
confidence interval.
Use 3 decimal places (3pts)
- Calculate a 95% confidence interval by hand
for the proportion of companies that report higher profits than
their actual profits. (3pts)
- Interpret the results of your confidence interval in context of
the problem.