Unit 1
"Health is a state of complete _______, ______, and _________ well-being and not merely the absence of _______ or _______"
"Health is a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity" - WHO
How are the mean, median, and mode calculated? Which are robust?
mean is not robust
median is robust
mode is robust
Sufficient or Necessary?: The exposure may or may not be present when the outcome is present because the outcome has other causes and can occur without the exposure
Sufficient but not necessary
Q1 = 20
Q2 = 80
Q3 = 50
IQR = 30
Solve the odd ratio of food poisoning from ice cream:
Exposed cases = 13
Exposed controls = 32
Unexposed cases = 17
Unexposed controls = 23
OR = odds that a case was exposed / odds that control was exposed
= (13/17)(32/23) = 0.55
What are the 3 core functions of Public Health?
Assessment, Policy Development, and Assurance
In a _______ study, we construct a sample based on exposure (E) and measure disease (D) over time in a population of disease-free individuals.
Cohort
Randomized clinical trial =Subjects from the population of interest are assigned
(randomly) a level of exposure by the investigator.
Case-Control = Construct a sample based on current disease status (D) and
measure the exposure (E) from the past.
Cross-sectional = Construct a sample without consideration of disease (D) or
exposure (E) — measure D and E at the same time.
What is the null and alternative hypothesis for and odds ratio?
null = 1 (there is no association between exposure and disease)
alt not = 1 (there is an association)
In Cameronsville, 40 out of 200 children under 5 years of age passed away in 2015. What is the Under 5 Mortality rate in this scenario?
200
Find the specificity and sensitivity of the following:
Diseased that test + = 180
Non-diseased that test + = 80
Diseased that test - = 20
Non-diseased that test - = 720
Sensitivity = 180/200 = 0.90
Specificity = 720/800 = 0.90
What is the difference between a parameter and a statistic?
Statistic = numerical value that describes a sample characteristic
Parameter = numerical value that describes a population characteristic
How many outcomes are possible in a Binomial Distribution?
2: successes and failures
We fail to reject the null hypothesis when the null hypothesis is false
Type II error
Create a 95% CI: "In order to estimate the average computer time spent on the computer terminals at a university, data were collected from a sample of 81 public health students over a 1 week period. Assume the population std. dev. is 1.2 hours. The sample mean was 9 hrs.
CI = sample mean +/- (1.96)(SE of the proportion)
SE = std dev/sqrt(n) = 1.2/sqrt(81)
CI = 9 +/- 1.96(0.133) = (8.733,9.2607)
The students in a certain Spanish class took two tests, reading and speaking. 25% of the class passed both tests, while 51% only passed the reading test. What is the probability of a student passing both tests, GIVEN that the student passed the reading test?
0.25/0.51=0.49
Descriptive Epidemiology organizes and analyzes data in order to understand patterns of health and disease by ______, ________, and _______.
Descriptive Epidemiology organizes and analyzes data in order to understand patterns of health and disease by PERSON, PLACE, and TIME.
In which Hill's causal Criteria does the exposure come before the outcome?
Temporality
Name three types of information bias
interviewer, recall, reporting
In a certain country with a population of 6 million people, 85,000 deaths occurred during the year ending in December 2001. Find the crude mortality rate
85000/6000000=0.0142 or 14.2 deaths per 1000
Cameron wants to travel to Dubai but she must have a negative covid test for 7 consecutive days to be able to board the plane. On average, 82% of her previous tests have been negative. What distribution would we use to find the amount of negative tests that we can expect Cameron to get
Binomial
E(x) = 7*0.82 = 5.74 tests
What is DALY and how is it equated?
Disability Adjusted Life Year = one lost year of "healthy" life
DALYs for a disease or health condition are calculated as the
sum of the Years of Life Lost (YLL) due to premature mortality
in the population and the Years Lived with Disability (YLD) for
people living with the health condition or its consequences.
DALY = YLL + YLD
What are the 3 conditions for a confounder?
1. The confounder must be associated with the exposure
2. The confounder must be an independent cause of the disease
3. The confounder CANNOT be an intermediate step in the causal pathway
Interpret the results for a risk ratio that had a confidence interval that does not include 0
We reject the null hypothesis that there is no difference between the risk of disease among the exposed and the risk of disease among the unexposed.
If A and B are independent events:
P(A) = 1/5
P(B)= 1/3
Find the intersection and union of A and B
intersection =P(A) * P(B) = 1/15
union = P(A) + P(B) - P(A intersection B) =1/5 + 1/3 - 1/15 =7/15
Anna(s) and Emily went to a fun BBQ where potato salad was served. Unfortunately, some of the guests got diarrheal disease immediately after the meal. If the probability of being diseased after eating potato salad is 0.77 and the probability of being diseased after not eating salad is 0.07, find the risk ratio of illness.
Risk = risk of disease among exposed / risk of diseases among unexposed
= 0.77/0.07 = 11 times the risk