Question

#7The mean diastolic blood pressure for a random sample of 60 people was 98 millimeters of mercury. If the standard deviation of individual blood pressure readings is known to be 9 millimeters of mercury, find a 95% confidence interval for the true mean diastolic blood pressure of all people. Then give its lower limit and upper limit.Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.Lower limit:?Upper limit:?

Answer 1

Explanation

The confidence interval formula is given by the formula below

$C.I=\bar{x}\pm z_c\frac{s}{\sqrt{n}}$$\begin{gathered} \bar{x}=98 \\ s=9 \\ z_c=1.960 \\ n=60 \end{gathered}$

Therefore, we will have;

$\begin{gathered} C.I=98\pm1.960\times\frac{9}{\sqrt{60}} \\ C.I=98±2.277 \\ C.I=95.723-100.277 \\ \end{gathered}$

Answer: Lower limit 95.7 and upper limit 100.3