Question

2. A scientist wishes to estimate the average diastolic blood pressure. He wants to be 99% confident that the estimate is accurate within 2 mm Hg. From a previous study, the standard deviation of the diastolic blood pressure was 4 mm Hg. What is the sample size required to estimate at this level precision?

Answer 1

Explanation:

x2 + 2√3x + 3 = 0

Comparing with ax2 + bx + c = 0, we get,

a = 1, b = , c = 3.

\ b2 – 4ac = ( )

2 – 4 × 1 × 3

= – 12 =

\ x =

–b ± √

...(Formula)

\ x = –2√ 3 ± √

=

–2√ 3 ±

\ x = –2√ 3

\ x =

\ The root of given quadratic equation is .