Question

In: Biology

100 people are tested for disease. 30 people have the disease and 70 do not. There...

100 people are tested for disease. 30 people have the disease and 70 do not. There were 20 true positives and 37 true negatives.
Part 1: What was the sensitivity of the test? Be sure to give context.
Part 2: What was the specificity of the test? Be sure to give context.
Part 3: What was the positive predictive value of the test? Be sure to give context.
Part 4: What was the accuracy of the test? Be sure to give context.

Expert Solution

100 people were Tested for the disease.

30 people have the disease and 70 do not. There were 20 true positives and 37 true negatives.

True positive (TP) = 20

True negative (TN) = 37

False positive (FP) = 30 - 20 = 10

False negative (FN) = 70 - 37 = 33

1) Sensitivity =

=

= 20/53 = 0.377

? Sensitivity is the ability of the test to correctly identify those with the disease i.e. true positive.

So the sensitivity of the test is 0.377

2) Specificity =

=

= 37/47 = 0.787

? Specificity is the ability of a test to correctly identify those without the disease i.e. true negative.

So the specificity of the test is 0.787

3) Positive predictive value =

=

= 20/57

= 0.351

? Positive predictive value is the proportion that the subjects with a positive screening truly have the disease.

So the positive predictive value is 0.351

4) Accuracy of the test

= Correctly predicted class × 100% Total Testing class

= TP + TN × 100% TP + TN + FP + FN

= 20 + 37 × 100% 100

= 57 %

Accuracy is the percentage of correctly classified instances i.e. percentage of true results in the population.

The accuracy of the test is 57%

gladiator answered 1 year ago

Suppose that 1000 people are randomly selected and tested for a particular disease that is present...

Suppose that 1000 people are randomly selected and tested for a particular disease that is present in 1.2% of the population. Assume that the test will perfectly identify the disease presence/abscence in each tested individual. For the following, for each numerical response, round your answer to at least 4 decimals(when necessary). -Use a binomial distribution to find the probability that at least 20 people test positive for the disease. -Approximate the previous probabilty by using the normal distribution. -Use a...

A new cold medication was tested by giving 125 people the drug and 100 people a...

A new cold medication was tested by giving 125 people the drug and 100 people a placebo. A control group consisted of 115 people who were given no treatment. The number of people in each group who showed improvement is shown in the table below. Cold Drug Placebo Control Total Improvement 72 55 38 165 No Improvement 53 45 77 175 Total 125 100 115 340 a) What is the probability that a randomly selected person in the study either...

There is 128 people with no disease and 397 with disease. Out of people with disease,...

There is 128 people with no disease and 397 with disease. Out of people with disease, 256 tested positive. Out of people with no disease, 1 tested positive. Suppose general disease probability is 0.1. What's the probability that a randomly picked person infected with the disease tests negative? (use Bayes theorem)

In a large population, 70% of the people have been vaccinated. If 6 people are random...

In a large population, 70% of the people have been vaccinated. If 6 people are random selected what is the probability that at least 3 adults are NOT vaccinated?

Disease A is autosomal dominant. A total of 4% of the study population of 100 people...

Disease A is autosomal dominant. A total of 4% of the study population of 100 people are affected. How many carriers are in the study population? Disease A is autosomal recessive. A total of 16% of the study population of 100 people are affected. How many carriers are in the study population? TIA!

What population(s) is/are at highest risk of contracting the disease? Are there any groups of people who should be tested?

answer this about Chagas Disease Population(s) affected: What population(s) is/are at highest risk of contracting the disease? Are there any groups of people who should be tested? Please include statistical/geographical data and trends (from the Centers for Disease Control and Prevention, World Health Organization, or other source [http://www.cdc.gov, http://www.who.int, etc.]).

Describe what happens to people who have Parkinson’s disease. What cells are affected and where do...

Describe what happens to people who have Parkinson’s disease. What cells are affected and where do they project to? What is the consequence on motor behavior and why? How does PD relate to Huntington’s disease (aka Huntington’s chorea)? How is PD different than other movement disorders like ALS and polio? One experimental treatment for PD involves injecting stem cells that produce a particular neurotransmitter into the brain: what neurotransmitter do you think it is and where do you think surgeons...

70% of people who are 30 years old will be alive ten years from now. In...

70% of people who are 30 years old will be alive ten years from now. In the random sample of 15 people, calculate the probability that... a) exactly 10 of them will be alive ten years from now b) at least 9 will be alive ten years from now c) at most 8 will be alive ten years from now d) how many of them would you expect to be alive 10 years from now e) let X be the...

Sickle-cell anemia is an autosomal recessive disease, people with the disease have a ss genotype and...

Sickle-cell anemia is an autosomal recessive disease, people with the disease have a ss genotype and people without the disease have a SS genotype. People who have the disease get very ill, but people who have only one copy of the recessive gene are actually protected from getting malaria (Ss heterozygote genotype). Which area of the world is the frequency of sickle cell anemia the highest? Why do you think this is true (related to heterozygote advantage)? We talked about...

A researcher tested a research hypothesis that people with diagnosed depression will have REDUCED level of...

A researcher tested a research hypothesis that people with diagnosed depression will have REDUCED level of depressive symptoms after a cognitive therapy treatment, as compared to the pre-treatment level of depressive symptoms. The cutoff t value is -1.746 for this one-tailed test. The data analysis yielded a mean change score (post-treatment minus pre-treatment) of -3. If the standard error is 2.0, what is the t statistic and what is the conclusion of the hypothesis test? -1.50; fail to reject the...