""invoices. Data are collected from a sample of 30 days, and the number of invoices processed and completion time, in hours,is stored in the file INVOICE.xls(see attachment).

(Hint: first determine which are the independent and dependent variables.)

a) Assuming a linear relationship, use the least-squares method to compute the regression coefficients B0 and b1.

b) Interpret the meaning of the Y intercept, B0, and the slope, B1, in this problem. Make answer comprehensive.

c) Use the prediction line developed in (a) to predict the amount of time it would take to process 150 invoices.

d) Determine the coefficient of determination, r square(r*r), and interpret its meaning.

e) Plot the residuals against the number of invoices processed and also against time.

f) Based on the plots in (e), does the model seem appropriate?

g) Compute the Durbin-Watson statistics and, at the 0.05 level of significance, determine whether there is any autocorrelation in the residuals.

h) Based on the result of (e) through (g), what conclusions can you reach concerning the validity of the model?

Use Excel or PhStat 2 (Excel Extension program)

invoices Processed time

149 2.1

60 1.8

188 2.3

19 0.3

201 2.7

58 1.0

77 1.7

222 3.1

181 2.8

30 1.0

110 1.5

83 1.2

60 0.8

25 0.4

173 2.0

169 2.5

190 2.9

233 3.4

289 4.1

45 1.2

193 2.5

70 1.8

241 3.8

103 1.5

163 2.8

120 2.5

201 3.3

135 2.0

80 1.7

29 0.5

"

- Sent to Statistics And Probability Expert Tutor on 5/11/2010 at 8:34am

You asked:

"this is the same proble from yesterday,, thanks"

- Sent to Statistics And Probability Expert Tutor on 5/11/2010 at 8:35am

You asked:

"have you seen this question,, I thought about using,, Least squares fit and a scatter plost of data,,could you help me with the questions? and working this problem"

- Sent to Statistics And Probability Expert Tutor on 5/11/2010 at 8:39am

You asked:

"1. Under what conditions should you use the /2 (chi-square) test to determine whether there is a difference between proportions of two independent populations?

2. Under what conditions should you use the /2 (chi-square) test to determine whether there is a difference between proportions of more than two independent populations?

3. Under What conditions should you use the /2 test of independence?

4. Under What conditions should you use the McNemar test?

5. What is a nonparametric procedure? Describe specifically when you would utilize a nonparametric test.

6. Under What conditions should you use the Wilcoxon sum rank test?

7 Under What conditions should you use the Kruskal-Wallis rank test?

(Hint: first determine which are the independent and dependent variables.)

a) Assuming a linear relationship, use the least-squares method to compute the regression coefficients B0 and b1.

b) Interpret the meaning of the Y intercept, B0, and the slope, B1, in this problem. Make answer comprehensive.

c) Use the prediction line developed in (a) to predict the amount of time it would take to process 150 invoices.

d) Determine the coefficient of determination, r square(r*r), and interpret its meaning.

e) Plot the residuals against the number of invoices processed and also against time.

f) Based on the plots in (e), does the model seem appropriate?

g) Compute the Durbin-Watson statistics and, at the 0.05 level of significance, determine whether there is any autocorrelation in the residuals.

h) Based on the result of (e) through (g), what conclusions can you reach concerning the validity of the model?

Use Excel or PhStat 2 (Excel Extension program)

invoices Processed time

149 2.1

60 1.8

188 2.3

19 0.3

201 2.7

58 1.0

77 1.7

222 3.1

181 2.8

30 1.0

110 1.5

83 1.2

60 0.8

25 0.4

173 2.0

169 2.5

190 2.9

233 3.4

289 4.1

45 1.2

193 2.5

70 1.8

241 3.8

103 1.5

163 2.8

120 2.5

201 3.3

135 2.0

80 1.7

29 0.5

"

- Sent to Statistics And Probability Expert Tutor on 5/11/2010 at 8:34am

You asked:

"this is the same proble from yesterday,, thanks"

- Sent to Statistics And Probability Expert Tutor on 5/11/2010 at 8:35am

You asked:

"have you seen this question,, I thought about using,, Least squares fit and a scatter plost of data,,could you help me with the questions? and working this problem"

- Sent to Statistics And Probability Expert Tutor on 5/11/2010 at 8:39am

You asked:

"1. Under what conditions should you use the /2 (chi-square) test to determine whether there is a difference between proportions of two independent populations?

2. Under what conditions should you use the /2 (chi-square) test to determine whether there is a difference between proportions of more than two independent populations?

3. Under What conditions should you use the /2 test of independence?

4. Under What conditions should you use the McNemar test?

5. What is a nonparametric procedure? Describe specifically when you would utilize a nonparametric test.

6. Under What conditions should you use the Wilcoxon sum rank test?

7 Under What conditions should you use the Kruskal-Wallis rank test?

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