You have collected data from 16 people on a health anxiety scale. The mean is 100 and the standard deviation is 40. What is the 95% confidence interval (to two decimal places):
A) (80.00, 120.00).
B) (78.69, 121.31).
C) (98.42, 101.58).
D) (94.70, 105.30).

Question

Quizplus · Accepted Answer

Using the formula for a 95% confidence interval, CI = X̄ ± 1.96 × (s/√n), where X̄ is the sample mean, s is the sample standard deviation, and n is the sample size, we get: 
CI = 100 ± 1.96 × (40/√16) 
CI = 100 ± 1.96 × 10 
CI = (78.69, 121.31) 
Therefore, the best answer choice is B.

You Have Collected Data from 16 People on a Health