Question

Acrylic bone cement is sometimes used in hip and knee replacements to fix an artificial joint in place. The force required to break an acrylic bone cement bond was measured for n = 44 specimens under specified conditions, and the resulting mean and standard deviation were 303.89 Newtons and 44.07 Newtons, respectively. Construct an "approximate" 95% confidence interval for the true average breaking force of the acrylic bone cement under the specified conditions, using t-critical = 2 as the approximate critical value. Lower endpoint: Upper endpoint: Note: Round your these endpoints to the nearest whole number.

Answer 1

SOLUTION:

From given data,

The force required to break an acrylic bone cement bond was measured for n = 44 specimens under specified conditions, and the resulting mean and standard deviation were 303.89 Newtons and 44.07 Newtons, respectively. Construct an "approximate" 95% confidence interval for the true average breaking force of the acrylic bone cement under the specified conditions, using t-critical = 2 as the approximate critical value.

where given

mean= = 303.89

standard deviation =s= 44.07

n= 44

degree of freedom = n-1 =44-1 = 43

so, At 95% confidence level positive t is,

= 1-95%

= 1-0.95

= 0.05

/2 = 0.05/2 = 0.025

t_critical = t_/2,df = t _0.025,43 = 2.017.

A 95% confidence interval for is

t_/2,df

The 95% confidence interval for the men is