Problem
A stock market analyst claims that seven of the stocks that make up the Dow Jones Industrial Average lost value from one hour to the next on one business day. Ten stock prices (in dollars per share) are recorded at one time during the day and then an hour later. To test the analyst's claim, we run a significance testing using Excel. Based on the information provided in the Excel output answer following questions:
α = 0.05
Show the EXCEL OUTPUT
|
Stock
|
Price (first hour)
|
Price (second hour)
|
|
1
|
283.72
|
282.85
|
|
2
|
41.46
|
41.62
|
|
3
|
64.27
|
64.21
|
|
4
|
69.12
|
68.21
|
|
5
|
173.54
|
174.19
|
|
6
|
35.57
|
35.45
|
|
7
|
90.85
|
90.19
|
|
8
|
72.15
|
73.18
|
|
9
|
57.93
|
56.65
|
|
10
|
103.3
|
103.1
|
A. What type of statistical test was used to answer the stock market analyst's research question? (Note: Is this a z-test or a t-test? One sample, dependent sample, or independent sample?)
B. Identify the claim and state the null and alternative hypothesis.
C. What is the critical value at the 5% level of significance? Be sure and include whether this critical value is a z or t value and, if appropriate, include the degrees of freedom associated with this statistical test.
D. What is the standardized test statistic?
E. What decision should be made about the analyst's claim? In other words, should you reject or retain the null hypothesis?
F. At 5% level of significance, is there enough evidence to support the analyst's claim? Interpret the decision in the context of the original claim.