Explain to your classmates the purpose of a critical value. What is it used for? Also, explain the difference in a one-tail test and two-tailed test. What causes these to be different and where would you use a one-tail test instead of a two-tailed test? Significance leads to the importance of testing. What is the purpose of the null hypothesis? What is the purpose of the alternative hypothesis? Explain what inferences or decisions you are able to make and not make from the tes

Answer:Step-by-step explanation:Hypothesis test is a method for derive  information of a big population  from data obtain from samples. So it is not a determinant procedure (in the sense that the results are exact ) is an evaluation dealing with probabilities, and parameters of a given distribution.In most cases the test implies decision based on the comparison of two homologous elements, one you compute from data of the sample, and the other one is settled down according to the level of confidence you want. Therefore you have:-Opposite hypothesisNull hypothesis  H₀ is the reference hypotes is what somebody says  about population ( companies about their products, label on boxes of food and so on)Alternative hypothesis Hₐ is always the opposite that means if;H₀  = somethingwe in the alternative hypothesis could settled down Hₐ  ≠ something from that point on, the investigation consist in showing which one is true-Elements you compute from data of the sample (normally call proof statistician )- Confidence interval (zone where with high probability we will find values of a random variable)-Critical values the fundamental element that is associated with the interval of confidence, and determine rejected and acceptance zone (for null hypothesis)From comparison emerge expressions such as    = ,  ≠ ,  ≤ ,  ≥ , < . >  and of course the  elements (that is)  a > b or wahtever is the comparisonSo what is a two tail test, a test in which we will evaluate data from sample and look if something is bigger or smaller One test tail (to the left )should be investigate in cases where the question is the calculated parameter is smaller than "certain value" (critical value) and one test tail (to the right) is for evaluation of parameters bigger than again "critical value"