Discuss the below:
Q1 You are a proprieter of NYC boutique. You want to know the average age of your customers. You take a random sample of 25 customers which yields an average age of 32 yrs with a standard deviation of 8. You have reason to belive the distibution of ages is normally distributed. Determine a 95% confidence interval for the age of your customers.
Q2 The monthly starting salaries of a student that recieved a MBA degree have a standard deviation of $70. What sample size should be selected so that there is 90% confidence of estimating the mean monthly income within a sampling error of $15 or less?
Q3 A random variable X has a poisson distribution with prameter u. A sample of 200 observations from this distribution has a mean equal to 3.4. Construct an approximate 90% confidence interval for u.
Q4 A survey is planned to determine the mean annual family expenses of employees of a large company. The management of the company wishes to be 95% confident that the sample mean is correct within +/- $50 of the true population meanof annual medical expenses. A pilot study indicated the population standard deviation can estiamted to be $400.
a) How large sample size is needed?
b) If management wants to be correct within +/- $25, what sample size is necessary?