Question

Use the graphing feature and the linear regression tool from the Data Analysis ToolPak in Excel to analyze the data found in Alligator mass/length data. After graphing the data, add a trendline and be sure to include R² and the equation of the line.

Length (ft)	Weight (lbs)
8.2	280
11.5	314
10.1	296
9.6	408
9.1	267
12.3	467
14.3	580
10.4	318
8.7	351
13.7	560
16.1	582
14.3	572
8.3	235
7.6	208
9.4	347
13.6	543
17.5	620
8.9	329
12.6	503
13.2	462
11.4	408
14.8	530
13.7	438
16.6	620
15.2	527

**Note: length = x-variable, weight = y-variable**

From your graph, R² = ______ (report to 4 decimals) (I got 0.871 but Im not sure if its right)

t-stat for the X-variable = _______ (report to 2 decimals)

P-value for the X-variable = _______ (copy & paste the answer exactly from Excel)

Based on the P-value, you will reject or fail to reject the null hypothesis. ________

Based on R² the regression is or is not a good fit for the data? _________

Can they use linear regression to predict the weight of the alligators from the length, yes or no? ________

If your findings support this method, use the equation from the trend line on the graph to determine the weight of an alligator 7ft in length. (report to 1 decimal) ________

If your findings do not support this method, report NA in the previous answer block.

Answer 1

we generated following graph and regression analysis using ms-excel

y=-68.39+41.43x

R²=0.8713

From your graph, R2 =0.8713(report to 4 decimals) (I got 0.871 but Im not sure if its right)

t-stat for the X-variable = 12.48 (report to 2 decimals)

P-value for the X-variable =0.000 (copy & paste the answer exactly from Excel)

Based on the P-value, you will reject or fail to reject the null hypothesis. Reject

Based on R2 the regression is or is not a good fit for the data? is (good fit)

Can they use linear regression to predict the weight of the alligators from the length, yes or no? ________Yes

If your findings support this method, use the equation from the trend line on the graph to determine the weight of an alligator 7ft in length. (report to 1 decimal) 221.6

for x=7, y=-68.39+41.43*7=221.6