SOLUTION: A random sample of twelve floor jacks is taken and the variable x represents the weight at which each jack fails under successively heavier loading (called the “failure rate of the

Algebra ->  Probability-and-statistics -> SOLUTION: A random sample of twelve floor jacks is taken and the variable x represents the weight at which each jack fails under successively heavier loading (called the “failure rate of the      Log On


   

Question 929450: A random sample of twelve floor jacks is taken and the variable x represents the weight at which each jack fails under successively heavier loading (called the “failure rate of the jack”) is recorded. The sample mean for the 12 recorded weights was 17.1 with a standard deviation of 5.41 tons. Assuming that the population of failure weights for all such jacks is normally distributed, what is the critical value required to form a 95% confidence interval (see attached graphic) for the mean failure weight for all such jacks?
17.1+-(Critical Value) 5.41/sqrt(12)

A 1.782
B 1.796
C 1.960
D 2.179
E 2.201
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

CI	

90%	z =1.645

92%	z = 1.751

95%	z = 1.960

98%	z = 2.326

99%	z = 2.576

.....

z = 1.960

C.