Step 1 :A Type I error, also known as a false positive, would occur if we reject the null hypothesis when it is actually true. In this case, it would mean concluding that the mean price has decreased (rejecting the null hypothesis) when in fact it has not (the null hypothesis is true).
Step 2 :A Type II error, also known as a false negative, would occur if we fail to reject the null hypothesis when it is actually false. In this case, it would mean failing to conclude that the mean price has decreased (failing to reject the null hypothesis) when in fact it has (the null hypothesis is false).
Step 3 :A correct decision would occur if we correctly reject the null hypothesis when it is false, or correctly fail to reject the null hypothesis when it is true. In this case, it would mean correctly concluding that the mean price has decreased when it has, or correctly failing to conclude that the mean price has decreased when it has not.
Step 4 :Final Answer: Type I error: Concluding that the mean price has decreased when it has not. Type II error: Failing to conclude that the mean price has decreased when it has. Correct decision: Correctly concluding that the mean price has decreased when it has, or correctly failing to conclude that the mean price has decreased when it has not.