Question

A random sample is used to estimate the mean time required for caffeine from products such as coffee or soft drinks to leave the body after consumption. A 95% confidence interval based on this sample is: 5.6 hours to 6.4 hours (for adults).

Answer 1

Answer:

Sample size n = 96.04

Explanation:

Given the interval is 5.6 hours to 6.4 hours

Let x be the midpoint, then x = (5.6+6.4)/2 = 6

Let E be the radius, then E = (6.4-5.6)/2 = 0.8/2 = 0.4

σ = 2 hours; as standard deviation is given and α = 0.05

Therefore, the sample size is:

$n=\left(\frac{1.96 * 2}{0.4}\right)^{2}=96.04$