Question

A zookeeper took a random sample of 30 days and observed how much food an elephant ate on each of those days. The sample mean was 350 kg and the sample standard deviation was 25 kg. Find the 95% confidence interval for how much food the elephant eats.

Answer 1

Answer:

341.95≤x≤358.95

Step-by-step explanation:

The confidence interval formula is expressed as;

CI = xbar±(z×s/√n)

xbar is the mean sample

s is the standard deviation

z is the z score at 95% confidence interval

n is the sample size

xbar = 350kg

z = 1.96

s = 25kg

n = 30

Substitute

CI = 350±(1.96×25/√30)

CI = 350±(1.96×4.564)

CI = 350±(8.946)

CI = (350-8.946, 350+8.946)

CI = (341.05, 358.95)

Hence the 95% confidence interval for how much food the elephant eats us 341.95≤x≤358.95