The manager of a large factory would like to know the time taken by the average worker to assemble a particular circuit board. She randomly samples 150 workers and records the time taken by each worker. The data are below.

Using the 'summary statistics' and 'statistical tables' functions in Gretl or excel to compute the necessary statistics, construct an approximate 95% confidence interval for the mean time taken to assemble the circuit board. Note: you may need to increase the number of decimal places provided by the 'summary statistics' function in Gretl or excel in order to calculate answers with the required accuracy.

(a) Enter the value of the upper bound of the confidence interval in the box below (rounded to 3 decimal places)

Answer

(b) Enter the value of the lower bound of the confidence interval in the box below (rounded to 3 decimal places)

16.47459

29.59694

310.67832

410.22965

512.87723

614.63097

715.14776

811.54811

916.88944

1014.28701

116.90151

129.56817

1311.75048

1410.42331

1511.40981

1612.98554

1711.04716

189.80565

199.66263

208.72481

2113.17109

2220.35022

239.84096

2411.19920

2511.11798

268.36782

2717.69453

289.91087

2926.84523

3014.97730

316.31209

3213.62627

337.57118

3411.69451

358.99686

367.28610

378.28519

3812.69185

397.66228

4025.85411

4117.76116

429.45883

4314.25519

4420.03267

4514.23467

4613.24970

4712.45807

488.63256

4912.12282

5015.40554

517.71125

5220.53863

537.48481

5426.89400

5513.00246

5620.70752

577.13896

5815.16547

5912.59627

6010.46662

6116.56084

6216.32234

6310.00997

647.42656

6515.36586

6612.68921

678.02992

688.06056

6911.28258

7021.03534

7115.27036

7212.21547

7315.80869

7412.35035

7519.58563

7611.73779

7710.18021

788.49973

798.96334

807.16935

8114.62627

8214.49278

8317.42750

8415.72236

8518.08269

869.41766

879.83786

888.70910

896.48802

909.78455

9110.47223

929.34087

9310.57583

9415.40738

9517.08518

9611.08245

9713.57259

9814.75769

9918.21193

10010.82411

10111.15793

10211.97513

10312.18739

10412.69195

10516.61101

1069.71077

1076.51020

10817.11848

10916.14332

1109.68541

1115.80865

11215.07319

11311.50632

11410.48869

1157.53977

11612.49741

11713.44659

11815.78496

11915.54937

12015.73712

12113.15453

1229.49128

1238.79288

1248.50490

12510.35081

12616.02420

12714.11505

1286.64871

12916.55085

1306.65799

13110.04777

1327.37511

13322.63645

1349.81337

13516.57587

13611.48114

13711.49514

13813.65242

13913.07809

1408.22868

1419.57166

14211.39814

14314.69875

14417.67395

14512.52372

14613.02953

14713.69085

14815.71965

14915.82469

15016.19935