Answer:
The 99% confidence interval = (126.93,157.67)
Step-by-step explanation:
The formula for Confidence Interval =
Mean ± z × Standard deviation /√n
Mean = 142. 3 mmHg
Standard deviation = 20.8 mmHg.
n = 12
Z score for 99% confidence interval = 2.56
Confidence Interval =
142.3 ± 2.56 × 20.8/√12
142.3 ± 2.56 × 6.0044427996
142.3 ± 15.371373567
Confidence Interval
= 142.3 - 15.371373567
= 126.92862643
≈ 126.93
142.3 + 15.371373567
= 157.67137357
≈ 157.67
Therefore, the 99% confidence interval = (126.93,157.67)
