Question

As reported by a sample study from the US National center for Health Statistics, the mean HDL cholesterol level of females 20 to 29 years old is 53.0, and the population standard deviation is known to be 13.4. Find the margin of error for a 99% confidence interval for the mean for a sample of 50 women.

Select one:

a. 1.8950

b. 3.7143

c. 0.6901

d. 4.8797

Answer 1

Solution :

Given that,

Point estimate = sample mean = = 53

Population standard deviation =    = 13.4

Sample size = n =50

At 99% confidence level the z is ,

  = 1 - 99% = 1 - 0.99 = 0.01

/ 2 = 0.01 / 2 = 0.005

Z/2 = Z0.005 = 2.576   ( Using z table )

Margin of error = E = Z/2* ( /n)

= 2.576* (13.4 / 50)

= 4.8797