1. Collette is self-employed, selling items at Home Interior parties. She wants to estimate the average amount a client spends at each party. A random sample of 35 clients' receipts gave a sample mean of $34.70 with population standard deviation $4.85.
1. Should you use the critical value (zc) or (tc) in determining a confidence interval in this problem? Explain.
2. Find a 90% confidence interval for the average amount expected to be spent by an individual.
3. Write a brief expanation of the meaning of the confidence interval in the context of this problem
4. For a party with 35 clients, use part (b) to estimate a range of dollar values for Collette's total sales at that party.