(10)A pharmaceutical company makes tranquilizers. It is assumed that the distribution for the length of time they last is normal. A random sample of patients showed the following lengths of time for the effectiveness of the tranquilizer in hours: 2.7 ; 2.8 ; 3.0 ; 2.3 ; 2.3 ; 2.2 ; 2.8 ;

2.1 ; 2.4 Show your work.

Construct a 90% confidence interval for the population mean length of time.

You may use the table on page 8 of this exam or a spreadsheet program such as Microsoft Excel or something siroUar Either way, you must show your relevant calculation. If you are using a spreadsheet program, you need to write down what you haved typed in and what value(s) it has returned.

(11)Registered nurses are said to earn an average annual salary of $69,110. Last year, a survey was conducted of 41 registered nurses in CA and it was found that this sample had a mean annual salary of $71,121 with a standard deviation of $7,489. Conduct a hypothesis test at a 95% confidence level to see if the average annual salary of registered nurses in CA is higher than $69,110. Show your work.

You may use the table on page 8 of this exam or a spreadsheet program such as Microsoft Excel or something siroi1ar. Either way, you must show your relevant calculation. If you are using a spreadsheet program, you need to write down what you have typed in and what value(s) it has returned.

z table:

z

o.oo

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.0

0.0000

0.0040

0.0080

0.0120

0.0160

0.0199

0.0239

0.0279

0.0319

0.0359

0.1

0.0398

0.0438 i 0.0478

0.0517

0.0557

0.0596

0.0636

0.0675

0.0714

0.0753

0.2

0.0793

0.0832

0.0871

0.0910

0.0948

0.0987

0.1026

0.1064

0.1103

0.1141

0.3

0.1179

0.1217

0.1255

0.1293

0.1331

0.1368

0.1406

0.1443

0.1480

0.1517

OA

0.1554

0.1591

0.1628

0.1664

0.1700

0.1736

0.1772

0.1808

0.1844

0.1879

0.5

0.1915

0.1950

0.1985

0.2019

0.2054

0.2088

0.2123

0.2157

0.2190

0.2224

0.6

0.2257

0.2291

0.2324

0.2357

0.2389

0.2422

0.2454

0.2486

0.2517

0.2549

0.7

0.2580

0.2611

0.2642

0.2673

0.2704

0.2734

0.2764

0.2794

0.2823

0.2852

o.e

0 .2881

0.2910

0.2939

0.2967

0.2995

0.3023

0.3051

0.3078

0.3106

0.3133

0.9

0.3159

0.3186

0.3212

0.3238

0.3264

0.3289

0.3315

0.3340

0.3365

0.3389

LO

0.3413

0.3438

0.3-\61

0.3485

0.3508

0.3531

0.3554

0.3577

0.3599

0.3621

Ll

0.3643

0.3665

0.3686

0.3708

0.3729

0.3749

0.3770

0.3790

0.3810

0.3830

L2

0.3849

0.3869

0.3B88

0 .3907

0 .3925

0 . 3 944

0.3962

0.3980

0.3997

0.4015

1.3

0.4032

0.4049

0.4066

0.4082

0.4099

0.4115

0.4131

0.4147

0.4162

0.4177

1A

0.4192

0.4207

0.4222

0.4236

0.4 251

0.4265

0.4279

0.4292

0.4306

0.4319

l.5

0.4332

0.4345

0.4357

0.4370

0.4382

0.4394

0.4406

0.4418

0.4429

0.4441

1.6

0.4452

0.4463

0.4474

0.4484

0.4495

0. 505

0.4515

J.4525

0.4535

0.4545

1.7

0.4554

0.4564

0.4573

0.4582

0.4591

0.4599

0.4608

0.4616

0.4625

0.4633

L8

0 .4641

0 .4649

0.4656

0.4664

0.4671

0.4678

0.4686

0.4693

0.4699

0.4706

L9

0.4713

0.4719

0.4726

0.4732

0.4738

0.4744

0.4750

0.4756

0.4761

0.4767

2.0

0.4772

0.4778

0.4783

0.4788

0.4793

0.4798

0.4803

0.4808

0.4812

0.4817

t table:

V

0.10

0.05

0.025

0.01

0.005

0.001

1

3.078

6.314

12.706

31,8 21

63.657

318.313

2

1.886

2.920

4.303

6.965

9.925

22.327

3

1.638

2.353

3.182

4.541

5.841

10.215

4

1.533

2.132

2.776

3.747

4.604

7.173

5

1.476

2.015

2.571

3.365

4.032

5.893

6

1.440

1.943

2.447

3.143

3.707

5.208

7

1.415

1.895

2.365

2.99B

3.499

4.782

8

1.397

1.860

2.306

2.896

3.355

4.499

9

1.383

1.833

2.262

2.821

3.250

4.296

10

1.372

1.812

2.228

2.764

3.169

4.143

11

1.363

1.796

2.201

2.71B

3.106

4.024

12

1.356

1.782

2.179

2.681

3.055

3.929

13

1.350

1.771

2.160

2.650

3.012

3.852

14

1.345

1.761

2.145

2.624

2.977

3.787

15

1.341

1.753

2.131

2.602

2.947

3.733

16

1.337

1.746

2.120

2.583

2.921

3.686

17

1.333

1-740

2.110

2.567

2.898

3.646

18

1.330

1.734

2.101

2.552

2.878

3.610