Statistics - THT 4

Statistics - THT 4 - PART 3 The null hypothesis is...

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Statistics Take Home Test 4 6/28/2006 1. The null hypothesis should be accepted, meaning that there are no significant differences in the effectiveness of these toothpastes in preventing cavities. Question 2 18 4 25 3 PART 2 Covariance 40 1 REAL ANSWER = -10.1 30 2 (Found by -8.41667*6/5 or by COV of sample) 50 2 -8.42 Used =COVAR(A11:A16,B11:B16) 20 3 but that is for a population (uses n instead of n-1) Correlation Coefficient 12.39 Used =STDEVA(A11:A16) 1.05 Used =STDEVA(B11:B16) Sxy/SxSy -0.78 PART 1
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Unformatted text preview: PART 3 The null hypothesis is accepted, meaning the population correlation coefficient is zero at the 5 percent significance level. This is true because the t-value of the sample is within the limits of the critcal t-value found using the 5% level of significance and the degree of freedom (4). ts = -2.47 tc = -2.77 15 20 25 30 35 40 45 50 55 0.5 1 1.5 2 2.5 3 3.5 4 4.5 No. of Accidents vs. Age in Years Age (in years) No. of Accidents...
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