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In: Statistics and Probability

An interval estimate for the average distance car tyres lasted during their "lifetime" was reported to...

An interval estimate for the average distance car tyres lasted during their "lifetime" was reported to be 34578 kilometres to 38512 kilometres. This interval estimate was based on a sample of 46 tyres. The variance of the lifetime was determined from previous studies to be 48512333 km squared. What level of confidence can be attributed to this interval estimate? State your answer as a percentage, correct to the nearest whole number.

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An interval estimate for the average distance car tyres lasted during their "lifetime" was reported to be 34578 kilometres to 38512 kilometres. This interval estimate was based on a sample of 46 tyres. The variance of the lifetime was determined from previous studies to be 48512333 km squared. What level of confidence can be attributed to this interval estimate?

Let be the mean and S be the standard deviation


Let Z be the critical normal distribution value for the given confidence interval

  

  

  

36545+1026.9494Z=38512

Z=1.9154

The area above Z = P(Z>1.9154)=0.0274

2(0.0274) = 0.054

1-0.054=0.946

This is a 94% confidence interval 95% approximately.

orchestra answered 2 years ago
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