Question: For each of the Summary Tables a through d, give a decision and a conclusion.

a. A study is conducted in which a number of people of low Socio-Economic-Status are checked for tuberculosis as are a number of people of higher Socio-Economic-Status. The question being addressed is if being of low Socio-Economic-Status increases the risk of tuberculosis.

Tuberculosis

Yes No

Low Socio- Yes 578 346389

Economic-

Status No 329 216721

Incidence rate of disorder among exposed = 0.0017

Incidence rate of disorder among non-exposed = 0.0015

Relative Risk = 1.0990

95%CI Lower Limit = 0.9600

95%CI Upper Limit = 1.2582

b. A study was conducted in which a number of patients with postoperative pulmonary complications were asked their age. A like number of patients without pulmonary complications were asked their age. The question being addressed is if being older than 70 years of age at the time of the operation increase the risk of postoperative pulmonary complications.

Postoperative Pulmonary Complications

Yes No

Older than 70 Yes 10 10

Years of Age No 201 437

Odds of exposure among those with the disorder = 0.0498

Odds of exposure among those without the disorder = 0.0229

Odds Ratio = 2.1741

95%CI Lower Limit = 0.8908

95%CI Upper Limit = 5.3065

c. A study was conducted determine if single session debriefing following a traumatic event prevents post traumatic stress disorder (PTSD). Some individuals were given the single session debriefing immediately following the traumatic event, other individuals were not debriefed. One year later, each individual was evaluated for PTSD.

PTSD

Yes No

Yes 57

(64.4803)

451

Debriefed (443.5197)

No 17

(9.5197)

58

(65.4803)

Expected Values are in parentheses

Df =1

Critical Ch Square: at alpha .05 = 3.8415 at alpha .01 = 6.6349

Ch Square Obtained = 7.7262

p = 0.0054

d. A correlational study was conducted to see if there is a relationship between the length of the postoperative hospital stay and the distance of the surgical site from the diaphragm.

Df = 177

r Obtained = 0.1142

p-value = 0.1280