Question

The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 24.8 for a sample of size 25 and standard deviation 11.8. Estimate how much the drug will lower a typical patient's systolic blood pressure (using a 99% confidence level). Assume the data is from a normally distributed population.

Enter your answer as a tri-linear inequality accurate to three decimal places.

? < μμ < ?

Answer 1

Solution :

degrees of freedom = n - 1 = 25 - 1 = 24

t/2,df = t0.005,24 = 2.797

Margin of error = E = t/2,df * (s /n)

= 2.797 * (11.8 / 25)

Margin of error = E = 6.601

The 99% confidence interval estimate of the population mean is,

- E < < + E

24.8 - 6.601 < < 24.8 + 6.601

18.199 < < 31.401