Help for you in maths questions

Help for you in maths questions

1.   Calculate Minimum Sample – Suppose a formal wear store determines that its customers population has a minimum age of 27 years and a maximum age of 62 years. What is the minimum sample size needed to construct a 90% confidence interval for the mean age of its customers, assuming a margin error of one year?

1.   2. Confidence Interval - Suppose you conduct a randomly assessment of 8 passengers age in a plane.  Assume the population is normally distributed.  Conduct a 95% & 98% confidence interval of the mean based on the sample.

sample ages: 7.0,3.5,8.6,15.8,14.7,7.8,0.5,4.2

1.   3. Confidence Interval for the Proportions – Suppose a pilot sample of 50 voters found that 30 of them voted in the last election. How many more voters must be sampled to construct a 95% internal with a margin error equal to 0.04?