We are only given the accuracy of the blood test and prevalence
of the disease in...
We are only given the accuracy of the blood test and prevalence
of the disease in our population. We are told that the blood test
is 98 percent reliable, this means that the test will yield an
accurate positive result in 98% of the cases where the disease is
actually present. Gestational diabetes affects 9 percent of the
population in our patient’s age group, and that our test has a
false positive rate of 12 percent. Use your knowledge of Bayes’
Theorem and Conditional Probabilities to compute the following
quantities based on the information given:
If 100,000 people take the blood test, how many people would
you expect to test positive and actually have gestational
diabetes?
What is the probability of having the disease given that you
test positive?
If 100,000 people take the blood test, how many people would
you expect to test negative despite actually having gestational
diabetes?
What is the probability of having the disease given that you
tested negative?
Comment on what you observe in the above computations. How does
the prevalence of the disease affect whether the test can be
trusted?
The prevalence of a disease D in the population is 10%. A new
test is introduced by a laboratory with the following
characteristics. The laboratory notes that if someone has the
disease, his or her test will be positive 90% of the time (P(pos|D)
= 0.90). However, a completely healthy individual will test
positive with probability 0.06 (P (pos|Dc) = .06).
(a) If we randomly select 5 people from this population, what is
the probability that all of them...
As health care workers we need to be aware of disease prevalence
and statistics affecting our community and individuals. One of the
functional roles of a Health Information Technician is to be
knowledgeable of the many disease processes, causes, prevention,
and treatment to ensure healthy outcomes. The World Health
Organization (WHO) is an important and factual resource that
provides yearly statistics as well as guidelines to prevent and
decrease the mortality of diseases and their processes.
Access the World Health...
Disease X has a low prevalence in population A, and high
prevalence in population B. Which of the following is true? (2
points)
The positive predictive value of a screening test will be
higher in population B compared to population A.
The positive predictive value of a screening test will be
higher in population A compared to population B.
The predictive value of a test is not related to the prevalence
of disease in a population.
None of the above....
A blood test indicates the presence of a particular disease 96%
of the time when the disease is actually present. The same test
indicates the presence of the disease 0.8% of the time when the
disease is not present. Two percent of the population actually has
the disease. Calculate the probability that a person has the
disease, given that the test indicates the presence of the
disease.
Q2: (a) The prevalence of a disease in a population is 0.02.
Explain the meaning of this in your own words. (1pt) (b) The
incidence rate of a disease in a population is 5 per 10,000 person
years. Explain the meaning of this in your own words. (1pt)
We wish to compare the prevalence of parasites in Mediterranean
fish to the prevalence of parasites in Atlantic fish. In the
Mediterranean Sea 500 brill were captured and dissected; 150 were
found to contain parasites In the Atlantic 200 brill
were captured and dissected; 40 were found to have parasites. In
what follows, let p1 denotes the infestation rate for
the Mediterranean brill and p2 denote the infestation
rate for the Atlantic brill. Find the margin of error for the...
G-Test of Independence
In a study of the relation between blood type and disease, large
samples of patients with peptic ulcers, patients with gastric
cancer, and control persons (free from any of these diseases) were
classified as to blood type (O, A, B, AB). In this problem, the
relatively small numbers of AB patients were omitted for
simplicity. The observed numbers are as follows:
Blood
Type
Peptic
Ulcer
Gastric
Cancer
Controls
O
983
383
2892
A
679
416
2625
B ...
The prevalence of a disease is the fraction of individuals who
are afflicted, i.e., the ratio of the number of cases to the whole
population. The incidence of a disease is the fraction of
individuals who become infected in one time period, usually one
year. This terminology is usually reserved for chronic diseases
such as diabetes or AIDS or cardiovascular disease, not for
seasonal flu or coronavirus. The prevalence is equal to the
incidence times the mean survival time. Thus...
Is the z-test the same as the t-test but only used when we know
the true value of population mean's variance? But in practice, I'm
assuming that the population mean's variance is never observed so
I'm confused why we use the z-test. When will the z-test be helpful
when the t-test is not if we never know the population mean's
variance in real life? What are the other two differences between
the two tests?