Statistics for Decision- Making in Business - Maricopa Community ...
Statistics for Decision- Making in Business - Maricopa Community ...
Statistics for Decision- Making in Business - Maricopa Community ...
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Homework Problems –6.2<br />
1. In a sample of 55 students from Arizona State University tak<strong>in</strong>g a political science class,<br />
30 say they would be <strong>in</strong>terested <strong>in</strong> tak<strong>in</strong>g another political science class. The university is<br />
<strong>in</strong>terested <strong>in</strong> determ<strong>in</strong>e the proportion of all its students that are <strong>in</strong>terested <strong>in</strong> tak<strong>in</strong>g<br />
another political science class.<br />
a. What is the population of <strong>in</strong>terest <strong>in</strong> this study<br />
b. Construct a 90% bootstrap confidence <strong>in</strong>terval <strong>for</strong>, , the true proportion.<br />
c. Interpret the real-world mean<strong>in</strong>g of your confidence <strong>in</strong>terval.<br />
2. A software company takes a random sample of recent orders and f<strong>in</strong>ds that, of the 250<br />
sampled, 42 resulted <strong>in</strong> the return of a piece of purchased software.<br />
a. What is the population of <strong>in</strong>terest <strong>in</strong> this study<br />
b. Construct a 99% bootstrap confidence <strong>in</strong>terval <strong>for</strong>, , the true proportion.<br />
c. Interpret the real-world mean<strong>in</strong>g of your confidence <strong>in</strong>terval.<br />
3. A batch of apples was <strong>in</strong>spected prior to shipment <strong>for</strong> any defects. Each apple was<br />
marked as either pass (P), re-<strong>in</strong>spect (R) or fail (F). The follow<strong>in</strong>g results were reported.<br />
F P P P P P P P R R<br />
P P R P R R P R P P<br />
P R P R P F R R P P<br />
P P P P P P P R P P<br />
P P P F P R P P P R<br />
a. What is the population of <strong>in</strong>terest <strong>in</strong> this study<br />
b. Construct a 95% bootstrap confidence <strong>in</strong>terval <strong>for</strong>, , the true proportion of<br />
pass<strong>in</strong>g apples.<br />
c. Interpret the real-world mean<strong>in</strong>g of your confidence <strong>in</strong>terval.<br />
d. Us<strong>in</strong>g the CLT <strong>for</strong> ̂‟s, construct a 95% confidence <strong>in</strong>terval (see blue box <strong>in</strong> this<br />
section). How does it compare to the bootstrap confidence <strong>in</strong>terval<br />
Chapter 7<br />
Hypothesis Test<strong>in</strong>g<br />
We are often faced with uncerta<strong>in</strong>ty. Specifically, we often want to know whether one product is<br />
better than the other, whether one group outper<strong>for</strong>ms another <strong>in</strong> some type of task, or how one<br />
manufactur<strong>in</strong>g process compares to another, among many other th<strong>in</strong>gs. How can we ever know<br />
The first step would be to conduct a study and collect data. The data must then be compared.<br />
<strong>Statistics</strong> <strong>for</strong> <strong>Decision</strong>-<strong>Mak<strong>in</strong>g</strong> <strong>in</strong> Bus<strong>in</strong>ess © Milos Podmanik Page 207