The report of a sample survey of 1014 says with 95% confidence,
The report of a sample survey of 1014 says with 95% confidence, between
9% and 15% of all Americans expect to spend more on gift this year than last year
2. What is the critical value of t for a 90% confidence interval with df-14? (Assume a 2-tail test)
3. What is the critical value of A 95% confidence interval based on a sample of 20? (Population standard deviation is unknown). Assume a 2tail test.
4. A survey of 30 random shoppers found a 95% confidence interval that shoppers will spend between $24.50 and 28.30. A second survey surveyed 25 random shoppers