Question

Stan's heart rate, in beats per minute, was measured 20 times at random. The results are 82, 84, 98, 112, 97, 93, 91, 87, 112, 87, 79, 80, 72, 82, 94, 89, 89, 74, 80, and 72 beats per minute. Construct a 99% confidence interval for Stan's mean heart rate. (82.5659, 92.8341) (80.4942, 92.8341) (82.5659, 94.9052) (82.4288, 92.9712) (80.4942, 94.9052)

Answer 1

Answer:

(80.4942, 94.9052)

Step-by-step explanation:

The sample mean is x = 87.7.

The sample standard deviation is s = 11.26.

At 99% confidence and 19 degrees of freedom, the critical value is t = 2.861.

The confidence interval is:

x ± t (s/√n)

87.7 ± 2.861 (11.26 / √20)

87.7 ± 7.2053

(80.4947, 94.9053)