SCENARIO 9-11-A
You Are the Quality Control Manager of a Water

question 65

Multiple Choice

SCENARIO 9-11-A
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
bottles to a 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 Scenario9-11-DataA.XLSX. $$\begin{array} { l l l l l l l l l l } 1495 & 1499 & 1502 & 1500 & 1491 & 1498 & 1498 & 1495 & 1488 & 1516 \\1513 & 1486 & 1504 & 1503 & 1493 & 1504 & 1489 & 1500 & 1495 & 1499 \\1501 & 1507 & 1511 & 1496 & 1486 & 1497 & 1510 & 1504 & 1493 & 1482 \\1511 & 1502 & 1520 & 1514 & 1486 & 1514 & 1500 & 1505 & 1512 & 1500 \\1504 & 1498 & 1503 & 1514 & 1474 & 1489 & 1488 & 1506 & 1517 & 1490\end{array}$$ Assume that the number of times the handles have been used to lift the bottles before they break
follows a normal distribution. You want to test to see if there is enough evidence that the mean
number of times the handles have been used to lift the bottles before they break is more than 1500.
-Referring to Scenario 9-11-A, the parameter of interest is

• A) the percentage of water bottles with broken handles that break after having been used to lift the bottles for more than 1500 times.
• B) the percentage of water bottles with broken handles that break after having been used to lift the bottles for less than 1500 times.
• C) the mean number of times the handles of the water bottles manufactured by your company have been used to lift the bottles before they break.
• D) the mean number of times the handles of all the water bottles on the market have been used to lift the bottles before they break.

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Definitions:

Mean

The arithmetic average of a set of numbers, obtained by dividing the sum of the numbers by the count of numbers.

P(Z > 3.00)

The probability that a value Z, on a standard normal distribution, is greater than 3.00.

Area

In geometry, the measurement of the extent of a two-dimensional surface or shape, expressed in square units.

P(Z < 3.00)

A statistical expression indicating the probability of a standard normal variable being less than 3.00.