MATLAB: An Introduction with Applications
6th Edition
ISBN: 9781119256830
Author: Amos Gilat
Publisher: John Wiley & Sons Inc
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Answer A-1 and C-1 Please
In June 2009, an onslaught of miserable weather in New England played havoc with people’s plans and psyches. However, the dreary weather brought a quiet benefit to many city neighborhoods. Police reported that the weather was a key factor in reducing fatal and nondeadly shootings (The Boston Globe, July 3, 2009). For instance, it rained in Boston on 22 days in June, when 15 shootings occurred. In 2008, the city saw rain on only eight days, and 38 shootings occurred. The table below shows the number of rainy days and the number of shootings that occurred in June from 2005 to 2009. [You may find it useful to reference the t table.]
| Number of Rainy Days | Number of Shootings | |||||
| June 2005 | 7 | 31 | ||||
| June 2006 | 15 | 46 | ||||
| June 2007 | 10 | 29 | ||||
| June 2008 | 8 | 38 | ||||
| June 2009 | 22 | 15 | ||||
SOURCE: The Boston Globe, July 3, 2009.
Click here for the Excel Data File
a-1. Calculate the sample
a-2. Interpret the sample correlation coefficient between the number of rainy days and crime.
multiple choice 1
-
The correlation coefficient indicates a positive linear relationship.
-
The correlation coefficient indicates a negative linear relationship. Correct
-
The correlation coefficient indicates no linear relationship.
b. Specify the competing hypotheses in order to determine whether the population correlation coefficient between the number of rainy days and crime is negative.
multiple choice 2
-
H0: ρxy ≥ 0; HA: ρxy < 0 Correct
-
H0: ρxy ≤ 0; HA: ρxy > 0
-
H0: ρxy = 0; HA: ρxy ≠ 0
c-1. Calculate the value of the test statistic. (Negative value should be indicated by a minus sign. Round intermediate calculations to at least 4 decimal places and final answer to 3 decimal places.)
Transcribed Image Text:Number of Rainy Days
Number of Shootings
June 2005
7
31
June 2006
15
46
June 2007
10
29
June 2008
8
38
June 2009
22
15
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