A random sample of n = 20 trees yields a mean diameter of 12.4 inches with s = 2.1 inches. Use t* = 2.093 for 95% confidence with df = 19.
What is the 95% confidence interval for the mean tree diameter?
- A
(12.30, 12.50)
- B
(10.30, 14.50)
- Ccheck_circle
(11.42, 13.38)
- D
(11.98, 12.82)
Explanation
ME = 2.093 * (2.1/sqrt(20)) = 2.093 * 0.4696 = 0.983. CI = 12.4 ± 0.98 = (11.42, 13.38).