9.1.2

Many high school students take the AP tests in different subject areas. In 2007, of the 144,796 students who took the biology exam 84,199 of them were female. In that same year, of the 211,693 students who took the calculus AB exam 102,598 of them were female ("AP exam scores," 2013). Estimate the difference in the proportion of female students taking the biology exam and female students taking the calculus AB exam using a 90% confidence level.

9.1.5

Are there more children diagnosed with Autism Spectrum Disorder (ASD) in states that have larger urban areas over states that are mostly rural? In the state of Pennsylvania, a fairly urban state, there are 245 eight year olds diagnosed with ASD out of 18,440 eight year olds evaluated. In the state of Utah, a fairly rural state, there are 45 eight year olds diagnosed with ASD out of 2,123 eight year olds evaluated ("Autism and developmental," 2008). Is there enough evidence to show that the proportion of children diagnosed with ASD in Pennsylvania is more than the proportion in Utah? Test at the 1% level.

9.2.6 The British Department of Transportation studied to see if people avoid driving on Friday the 13th. They did a traffic count on a Friday and then again on a Friday the 13th at the same two locations ("Friday the 13th," 2013). The data for each location on the two different dates is in table #9.2.6. Estimate the mean difference in traffic count between the 6th and the 13th using a 90% level.

Dates 6th 13th

1990, July 139246 138548

1990, July 134012 132908

1991, September 137055 136018

1991, September 133732 131843

1991, December 123552 121641

1991, December 121139 118723

1992, March 128293 125532

1992, March 124631 120249

1992, November 124609 122770

1992, November 117584 117263

9.3.4 A study was conducted that measured the total brain volume (TBV) (in ) of patients that had schizophrenia and patients that are considered normal. Table #9.3.5 contains the TBV of the normal patients and table #9.3.6 contains the TBV of schizophrenia patients ("SOCR data oct2009," 2013). Compute a 90% confidence interval for the difference in TBV of normal patients and patients with Schizophrenia.

Table #9.3.5: Total Brain Volume (in ) of Normal Patients

1663407

1583940

1299470

1535137

1431890

1578698

1453510

1650348

1288971

1366346

1326402

1503005

1474790

1317156

1441045

1463498

1650207

1523045

1441636

1432033

1420416

1480171

1360810

1410213

1574808

1502702

1203344

1319737

1688990

1292641

1512571

1635918

Table #9.3.6: Total Brain Volume (in ) of Schizophrenia Patients

1331777

1487886

1066075

1297327

1499983

1861991

1368378

1476891

1443775

1337827

1658258

1588132

1690182

1569413

1177002

1387893

1483763

1688950

1563593

1317885

1420249

1363859

1238979

1286638

1325525

1588573

1476254

1648209

1354054

1354649

1636119

11.3.2

Levi-Strauss Co manufactures clothing. The quality control department measures weekly values of different suppliers for the percentage difference of waste between the layout on the computer and the actual waste when the clothing is made (called run-up). The data is in table #11.3.3, and there are some negative values because sometimes the supplier is able to layout the pattern better than the computer ("Waste run up," 2013). Do the data show that there is a difference between some of the suppliers? Test at the 1% level.

Table #11.3.3: Run-ups for Different Plants Making Levi Strauss Clothing

Plant 1

1.2

10.1

-2

1.5

-3

-0.7

3.2

2.7

-3.2

-1.7

2.4

0.3

3.5

-0.8

19.4

2.8

13

42.7

1.4

3

2.4

1.3

Plant 2

16.4

-6

-11.6

-1.3

4

17

3.8

4.3

10.4

4.2

8.5

6.3

9

7.1

4.3

19.7

3

7.6

70.2

8.5

6

2.9

Plant 3

12.1

9.7

7.4

-2.1

10.1

4.7

4.6

3.9

3.6

9.6

9.8

6.5

5.7

5.1

3.4

-0.8

-3.9

0.9

1.5

Plant 4

11.5

10.2

3.8

8.3

6.6

10.2

8.8

2.7

5.1

11.2

5.9

13

6.8

14.5

5.2

7.3

7.1

3.4

0.7

Plant 5

24

-3.7

8.2

9.2

-9.3

8

15.8

22.3

3.1

16.8

11.3

12.3

16.9

11.3.4

A study was undertaken to see how accurate food labeling for calories on food that is considered reduced calorie. The group measured the amount of calories for each item of food and then found the percent difference between measured and labeled food, . The group also looked at food that was nationally advertised, regionally distributed, or locally prepared. The data is in table #11.3.5 ("Calories datafile," 2013). Do the data indicate that at least two of the mean percent differences between the three groups are different? Test at the 10% level.

Table #11.3.5: Percent Differences Between Measured and Labeled Food

National Advertised

2

-28

-6

8

6

-1

10

13

15

-4

-4

-18

10

5

3

-7

3

-0.5

-10

6

Regionally Distributed

41

46

2

25

39

16.5

17

28

-3

14

34

42

Locally Prepared

15

60

250

145

6

80

95

3