Explain to your classmates the purpose of a critical value.

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 test.