Visitors to an e-commerce website arrive at the site in one of four ways: by dir
ID: 3335888 • Letter: V
Question
Visitors to an e-commerce website arrive at the site in one of four ways: by direct access (the visitor types the site's URL into a browser or clicks on a bookmark); via a link on another website, e-mail message, or banner ad; from a paid listing generated by a search engine; or via an organic (unpaid) listing generated by a search engine.
Engine Ready, an Internet marketing company, randomly selected 27 U.S. e-commerce companies from its 500 clients and studied a total of 18.7 million visits over a 2 - year period. For each visit, data were collected on the traffic source and the size of the order placed by the visitor (in dollars). (If no order was placed, the order size is 0.) The relative frequency and average order size for each traffic- source type are shown in the following table.
Traffic Source
Relative Frequency
Average Order (Dollars)
Direct Access
0.20
5.69
Link
0.14
5.01
Paid Search Ad
0.41
1.91
Search Result
0.25
1.35
Suppose that Sparkle Motion, an online jewelry retailer, conducts a test of the hypothesis that its traffic- source proportions are the same as the traffic- source proportions for the 18.7 million website visits in the Engine Ready study. It selects a random sample of visits to its website and categorizes each visit according to the visit's traffic source. The resulting category counts are shown in the following table.
Traffic Source
Observed Frequency
Direct Access
31
Link
18
Paid Search Ad
93
Search Result
58
The expected frequency for the paid search ad category is________.
The Sparkle Motion statistician confirms that the expected frequencies for each of the four categories is 5 or more and proceeds to compute the chi- square test statistic. The contribution of the paid search ad category is_______.
The value of the test statistic is x2 = ________.
Using the critical value approach, the null hypothesis (that p1= 0.20, p2 = 0.14, p3= 0.41, and = 0.25) is ___________.
The p-value is ______.
At a significance level of a = 0.10, using the p-value approach, the null hypothesis (that p1= 0.20, p2 = 0.14, p3 = 0.41, and p4= 0.25) is ________.
Consider the average order size for the four traffic- source types from the Engine Ready study. A comparison of the observed and expected frequencies from the Sparkle Motion study suggests that the average amount spent during a visit to the Sparkle Motion website is __________ the average amount spent during the visits covered by the Engine Ready Study.
Traffic Source
Relative Frequency
Average Order (Dollars)
Direct Access
0.20
5.69
Link
0.14
5.01
Paid Search Ad
0.41
1.91
Search Result
0.25
1.35
Explanation / Answer
Ans:
The contribution of the paid search ad category is 1.476
Test statistic:
Calculated chi square score=8.352
df=4-1=3
p-value=CHIDIST(8.352,3)=0.0393
As,p-value<0.1,We reject null hypothesis.
There is suffcient evidence that distribution is not as given above(p1= 0.20, p2 = 0.14, p3 = 0.41, and p4= 0.25)
Category Relative freq.(pi) Expected (O)=200*pi Direct access 0.2 40 Link 0.14 28 Paid search ad 0.41 82 Search result 0.25 50 Total 1 200Related Questions
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