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Confidence Interval for Mean: Tesla Motors

Tesla Motors needs to buy axles for their new car. They are considering using Chris Cross Manufacturing as a vendor. Tesla's requirement is that 95% of the axles are 100 cm ± 2 cm. The following data is MegaStat output from a test run from Chris Cross Manufacturing. Should Tesla select them as a vendor? Explain your answer.

Descriptive statistics

count 16
mean 99.850
sample variance 4.627
sample standard deviation 2.151
minimum 96.9
maximum 104
range 7.1

population variance 4.338
population standard deviation 2.083

standard error of the mean 0.538

tolerance interval 95.45% lower 95.548
tolerance interval 95.45% upper 104.152
half-width 4.302

1st quartile 98.850
median 99.200
3rd quartile 100.550
interquartile range 1.700
mode 103.000

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Solution Summary

The solution provides step by step method for the calculation of confidence interval for mean. Formula for the calculation and Interpretations of the results are also included. Interactive excel sheet is included. The user can edit the inputs and obtain the complete results for a new set of data.