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Using the data given in the table below, answer the following questions. (Round

ID: 3063645 • Letter: U

Question

Using the data given in the table below, answer the following questions. (Round your final answers to 3 decimal places.) Order Size and Shipping Cost (n = 12) Orders (X) Ship Cost (Y)

1,078 4,402

1,045 5,589

744 3,228

867 4,135

1,119 4,790

1,115 5,408

817 4,452

952 5,557

721 3,308

636 3,598

1,176 6,662

1,052 5,014

(a) Use Excel, MegaStat, or MINITAB to calculate the correlation coefficient.

rcalc =

(b) Use Excel or Appendix D to find t.025 for a two-tailed test at a=0.05.

t.025 ± =

(c) Calculate the t test statistic.

tcalc =

(d) Should we reject the null hypothesis of zero correlation?

No or Yes

Explanation / Answer

The statistical software output for this problem is:

Simple linear regression results:
Dependent Variable: y
Independent Variable: x
y = 221.38968 + 4.7241056 x
Sample size: 12
R (correlation coefficient) = 0.82662463
R-sq = 0.68330827
Estimate of error standard deviation: 610.40114

Parameter estimates:


Analysis of variance table for regression model:

Hence,

a) rcalc = 0.827

b) t0.025 = + 2.634

c) tcalc = 4.645

d) Yes

Parameter Estimate Std. Err. Alternative DF T-Stat P-value Intercept 221.38968 975.60337 0 10 0.22692591 0.8251 Slope 4.7241056 1.0170203 0 10 4.6450456 0.0009
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