SCENARIO 8-13-B
You Are the Quality Control Manager of a Water

SCENARIO 8-13-B
You are the quality control manager of a water bottles company. One of the biggest complaints in the
past years has been the breakage and, hence, the concern on the durability of the connector between
the lid and the bottle which many users use as a handle for the bottles. To collect evidence before
implementing any modification to the production process, your department has subjected 50 water
bottle to durability test and the following data on the number of times the handles have been used to
lift the bottles before they break are contained in the file Scenario8-13-DataB.XLSX. $$\begin{array} { l l l l l l l l l l } 493 & 506 & 515 & 491 & 500 & 505 & 517 & 510 & 506 & 503 \\503 & 491 & 495 & 496 & 496 & 505 & 493 & 486 & 504 & 483 \\514 & 494 & 497 & 501 & 493 & 490 & 510 & 494 & 494 & 495 \\494 & 486 & 495 & 506 & 506 & 507 & 502 & 498 & 510 & 501 \\500 & 505 & 492 & 486 & 501 & 496 & 501 & 521 & 510 & 498\end{array}$$ Assume that the population standard deviation is 5 and the number of times the handles have been
used to lift the bottles before they break follows a normal distribution.
-Referring to Scenario 8-13-B, the critical value used to construct the 95% confidence interval for
the mean number of times the handles have been used to lift the bottles before they break is _____.