Please can you help me explain the difference between Type I

Please can you help me explain the difference between Type I and Type II errors in Hypothesis testing (use an example to describe answer)?

Solution

Type I error is when you reject the null hypothesis when it is true.

Suppose you want to test a hypothesis that H0 : p= 0.5 against H1 : p= 0.8.

Here type I error will occur when you will reject p= 0.5 i.e you say that p= 0.8/when the true value for p is infact 0.5.

Type 2 error is when you accept you null hypothesis when in reality your alternative hypothesis is true.

i.e. for the above hypothesis there will be type 2 error when you say that the p value is 0.5 when in reality it is 0.8.