Statking

There are two types of ERROR that we will dealing during conducting hypothesis testing; TYPE I ERROR: The probability of rejecting the Ho when Ho is TRUE. TYPE II ERROR: The probability of accepting the Ho when Ha is TRUE. TYPE I ERROR is serious form of error thus, it is denoted by alpha and is commonly referred as the SIGNIFICANCE LEVEL. TYPE II ERROR is usually denoted by beta where 1-beta is the POWER OF THE TEST. POWER OF THE TEST is the probability of rightly rejecting Ho when it is FALSE. In order words, we are RIGHT on deciding to accept Ha as our decision. There are some factors need to be considered when looking into the power of the test; When the significance level or a is made smaller, then the power will be decreases. In condition where the standard deviation of individual observation increases, the power will be decreases. By increasing sample size, then the power will be increasing too. The power of the test will be increases if the alternative me...

When we are conducting hypothesis testing, there will be four possible outcomes can occur: i.                We accept Ho, and Ho is in fact TRUE ii.               We accept Ho, and Ha is in fact TRUE iii.             We reject Ho, and Ho is in fact TRUE iv.              We reject Ho, and Ha is in fact TRUE In practice, it is impossible to prove the Ho (null hypothesis) is TRUE. Therefore, if we ACCEPT Ho, then we have actually FAILED to reject Ho! If Ho is TRUE and Ho is accepted, or if Ha is TRUE and Ho is rejected, then the correct decision has been made. Therefore, if we accidently rejecting Ho when Ho is actually TRUE, or if Ha is TRUE but now Ho is accepted, then an ERROR has been made. So now the two concepts of ERROR...

If we not able to randomly assign people,  we have the following type of study called a cohort study. A defined population not randomly assigned with self selected or assigned by other people to exposure to non-exposure. People for example may work at certain industrial plan. Others seek job at another plan. And then we follow-up people who have the exposure and people who don’t have the exposure and look at the rate of the disease at both groups. If indeed the exposure is related to the disease we would expect to see a greater number of people with the disease in the exposure group than the non-expose group.

I like to turn to the basic study design therefore used to confirm or refute the hypothesis. The first type of study, randomised trial also called as randomised clinical trial because it often use to testing new therapy. What is the design showing here? We begin with a study population and we randomly assign the study population into current treatment or new treatment. We then follow up both groups of patients and determine how many dies from the disease in current treatment and how many dies from the disease in new treatment. If the new treatment is more effective than the current treatment we would expect to see fewer people die from the disease in the new treatment than we see in current treatment.  So the design of randomised trial is basically a simple one. And it is very desirable type of study.  The act can be carried only if we looking at a potentially beneficial prevention. If we have toxic or potentially toxic substances or putative carcinogens clearly we cannot r...

If you wanted to know about adverse heath outcomes in human population, you need to study human population. You can make excellent study on the rodents for the example, even the best of such study means we have to extrapolate from species to another, and therefore the study on human being is critical. Epidemiology plays this role. What is epidemiology? It is the study of how disease distributes in human populations and what determines differences in disease risk among different population subgroups. Why one group of people have high risk of developing disease than another. What we can learn from that? How that can help us to prevent diseases? And if we turn on how the epidemiology is use, there are many uses in which three we will shown here. First the epidemiology helps us to assess the magnitude of the community burden of disease. How much disease? What type of disease in our community? Second the epidemiology helps us to identify the causes of human disease. A critical factor i...

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