Type I & Type II Errors: Videos & Practice Problems

Describe a Type I & Type II Error for each scenario.
$\left(A\right)$ A snack company guarantees that each bag contains at least 200 g of chips.

• A. Type I: We conclude that some bags don't have at least $200 g$ when they all do.Type II: We conclude that some bags don't have at least 200 g when they all do.
• B. Type I: We conclude all bags have at least $200 g$ when some don'tType II: We conclude all bags have at least $200 g$ when some don't
• C. Type I: We conclude that all bags have at least $200 g$ when some don't.Type II: We conclude that some bags don't have at least $200 g$ when they all do.
• D. Type I: We conclude that some bags don't have at least $200g$ when they all do.Type II: We conclude all bags have at least $200g$ when some don't.

Answer: (D)

Describe a Type I & Type II Error for each scenario.
$\left(B\right)$ A computer repair store advertises the average repair cost as \$75 or less.

• A. Type I: We conclude the average repair cost is more than $\$75$ when it's actually $\$75$ or less.Type II: We conclude the average repair cost is $\$75$ or less when it's more than that.
• B. Type I: We conclude the average repair cost is more than $\$75$ when it's actually $\$75$ or less.Type II: We conclude the average repair cost is more than $\$75$ when it's actually $\$75$ or less.
• C. Type I: We conclude the average repair cost is $\$75$ when it's actually more than \$75.Type II: We conclude the average repair cost is $\$75$ or less when it's actually $\$75$ or less.
• D. Type I: We conclude the average repair cost is $\$75$ or less when it's more than that.Type II: We conclude the average repair cost is $\$75$ or less when it's more than that.

Answer: (A)

A furniture manufacturer claims that the mean production cost of a dining chair is \$50. Management wants to test if the cost has increased. What are the Type I & Type II Errors? Which is more serious?

• A. Type I: We conclude that μ > 50 when actually μ = 50.Type II: We conclude that μ = 50 when actually μ > 50.Type I is more serious.
• B. Type I: We conclude that μ = 50 when actually μ > 50.Type II: We conclude that μ > 50 when actually μ = 50.Type I is more serious.
• C. Type I: We conclude that μ > 50 when actually μ = 50.Type II: We conclude that μ = 50 when actually μ > 50.Type II is more serious.
• D. Type I: We conclude that μ = 50 when actually μ > 50.Type II: We conclude that μ > 50 when actually μ = 50.Type II is more serious.

Answer: (C)