Question

FIREARM DEATHS Download the Excel file Firearm.xls for use in this question. The number of deaths due to firearms in the United States between 1968 and 1993 are given in the Excel file.
Answer the following using the research hypothesis, "there is a correlation between year and number of firearm deaths in the US."

• A. What is the value of the correlation coefficient between year and number of firearm deaths?  (Answer to 3 decimal places)

• B. How many degrees of freedom does your data have?

• C. What is the critical value of your test statistic?

• D. Is there evidence of a significant trend in firearm deaths over this period?  (yes/no)
• 
  . Arial Paste Cut Copy Format x Β Ι Ο B5 fx 29 firearm deaths (thousands) 24 29 33 1 year 2 1968 3 1969 1970 1971 6 1972 7 1973 3 1974 9 1975 10 1976 11 1977 12 1978 13 1979 14 1980 15 1981 16 1982 17 1983 18 1984 19 1985 20 1986 21 1987 22 1988 23 1989 24 1990 25 1991 26 1992 27 1993 34 33 30 33 34 35 41 28
  
• I submitted this test a few times but I keep getting different answers now I'm so confused I don't even know what to study can I get an expert on this please. Thanks

Answer 1

Let's find out the correlation coefficient in Microsoft Excel. Go to Data -> Data Analysis -> Correlation. Now input the following into the dialog box and click OK.

F G H I J ? X nm tonooooo ок $A$2:$B$28 Cancel O Columns O Rows Help A B C D E 2 Year Firearm deaths (thousands) 1968 231 1969 Correlation 1970 27 Input 1971 Input Range: 1972 1973 Grouped By: 1974 1975 Labels in First Row 1976 Output options 1977 1978 O Output Range: 1979 New Worksheet Ply: 1980 New Workbook 1981 1982 1983 1984 31 1985 1986 34 22 1987 1988 34 30 33; 23

After you are done, we will get the output for the correlation coefficient.

	Year	Firearm deaths (thousands)
Year	1
Firearm deaths (thousands)	0.859751	1

a) Correlation coefficient = 0.860

b) Degrees of freedom = n - 2 = 26 - 2 = 24

c) Let's find out the critical value of the chi-square statistic at df = 24 and alpha = 0.05 (assume) from the table.

Critical value = 0.381

d) As the correlation coefficient = 0.860 > 0.381, there is evidence of a significant trend in firearm deaths over this period. Answer is YES