• Occurs when the null hypothesis is rejected while it is true.
• The p-value of 0.05 means there’s a 5% probability that the result is due to chance.

Type I Error: α

• False positive.
• H0 is true but falsely rejected.
• significance level (α) is the probability of making a type I error.
• Α is usually set at 0.05

Type II Error: β

• False negative.
• H0 is false but falsely accepted.
• The probability of making type II error β is usually set at 0.1-0.2.