A multicenter trial was conducted in 958 children 2-59 months of age with very severe pneumonia to compare the efficacy of two antibiotic regimens: injectable ampicillin plus gentamicin versus chloramphenicol, the standard of care. The study was conducted between August 2000 and April 2004 in eight sites in seven countries: (India, Bangladesh, Ecuador, Zambia, Mexico, Pakistan and Yemen).

Treatment failure was defined as any of the following occurring by five days after entry into the study:

• New development or persistence of at least two of the following: inability to drink; tachypnea (50 breaths/min in children aged 2-11 months and 40 breaths/min in children aged 12-59 months), and abnormally sleepy or difficult to wake
• Development or diagnosis of any of the following: bacterial meningitis, empyema, septic shock, renal failure, or newly diagnosed comorbid conditions
• Serious adverse drug reaction
• Modification of antibiotic treatment
• Voluntary withdrawal or absconding
• Death

Use the PS3_data.csv file to answer the following questions. The dataset contains only two variables with the following coded values:

Name of variable	Values
arm	1= Chloramphenicol; 2 = Ampicillin/Gentamicin
treat_fail	1 = Treatment failure; 0 = Not treatment failure

Answer the questions below based on the following dataset exported from R Studio.

> PS3_data <- read.csv("~/Test 1/PS3_data.csv")

>View(PS3_data)

> View(PS3_data)

> View(PS3_data)

> attach(PS3_data)

> table(treat_fail)

treat_fail 0 1

827 131

> prop.table(table(treat_fail))

treat_fail

0 1

0.8632568 0.1367432

> table(treat_fail, arm)

arm

treat_fail 1 2

0 402 425

1 77 54

> prop.table(table(treat_fail,arm),2)

arm

treat_fail 1 2

0 0.8392484 0.8872651

1 0.1607516 0.1127349

>

> View(PS3_data)

Use the R Studio output to answer the following questions:

1. What is the risk of treatment failure? (5 points)
2. Interpret the risk of treatment failure in the study population. (5 points)
3. What is the risk of treatment failure for children by treatment arm? (10 points)
4. What is the relative risk comparing the ampicillin/gentamicin arm to the standard of care (chloramphenicol) arm? (5 points)
5. Interpret the relative risk for treatment failure in this study. (5 points)
6. Calculate the risk difference in this dataset for treatment failure comparing children in the ampicillin/gentamicin arm to the standard of treatment (chloramphenicol) arm. (5 points)
7. Interpret the risk difference in this dataset for treatment failure comparing children in the ampicillin/gentamicin arm to the standard of treatment (chloramphenicol) arm. (5 points)