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Gutierrez Google Chrome D op Secure I https://www math dent/Player Test aspx?tes

ID: 3237293 • Letter: G

Question

Gutierrez Google Chrome D op Secure I https://www math dent/Player Test aspx?testld 153524022&centenwinsyes; Math 2 Hybrid Spring 2017 Test Math 2 Final Exam (Due Thursday by 11:00 pm) This Question: 1 pt Lab Time Remaining: 01 40 17 Submit Test 4 10 of 30 (9 complete) This Test: 30 pts possible Astudy of the ages of motorcyclistskilled in crashes involves the random selecton of 166 drivers with a mean of3130 years Assuming that. 118 years, constvotandinterpret a 95% contdence interval estimate of the mean age of all motorcyclists killed in crashes. ack here to yiewatdistributon table. LLE mmeules Luut What is the 95% confidence interval for the populaton mean w? ter contei -w- Round to two decimal places as needed.) Notice that the confidence intervallimits do notinclude ages below 20 years. What does this mean? s for Succe O A. The mean age ofthe populaton will never be less than 20 years old. ework O B. The mean age of the sample wllmost likely not be less than 20 years old. O C. Motorcyclists under the age of20 never die in crashes zes & Test O D. The mean age of the population w mostlikely not be less than 20 years old. crunch ons and nments Click o seiect your answer(s) Welcome to MyStatLab! rm Cortana Ask me anything

Explanation / Answer

Mean = 31.34 years
sigma = 11.8 years
A 95% Ci is given by:

xbar +/- Z*Sigma/sqrt(N)
=31.34 +/- 1.96*11.8/sqrt(166)
=29.544 to 33.135

Since there isn't 20 in the range we conclude that:

D. is the right conclusion.

> The statement should be about the mean age of population and not sample

> We can never say "never be less". We should say "most likely not be less than 20 years"