Statistical Hypotheses

Define a Type I error?

• The failure to reject a false null hypothesis
• Rejecting a true null hypothesis
• The acceptance to reject a null hypothesis
• Accepting a true null  hypothesis

Which of the following represents the appropriate null & alternative hypotheses?

The mean height of women is greater than 64"

• H₀: μ > 64"

  Hₐ: μ ≠ 64"

• H₀: μ < 64"

  Hₐ: μ > 64"

• H₀: p > 64"

  Hₐ: p ≠ 64"

• H₀: p = 64"

  Hₐ: p > 64"

Suppose the P-value for a hypothesis test is 0.0304. Using a = 0.05, what is the appropriate conclusion?

• a) Reject the null hypothesis

• b) Reject the alternative hypothesis

• c) Fail to reject the null hypothesis

• d) Fail to reject the alternative hypothesis

When p-value is greater than alpha we:

• Reject Ho

• Fail to reject Ha

• Fail to reject Ho

• Reject Ha

A mayor is concerned about the percentage of city residents who express disapproval of his job performance. His political committee pays for a newspaper ad, hoping to keep his disapproval rating below 21%. They will use a follow up poll to access effectiveness. What are the correct null and alternative hypotheses?

• Ho: μ > 21

  Ha: μ < 21

• Ho: p > .20

  Ha: p < .20

• Ho: p < .21

  Ha: p > .21

• Ho: p > .21

  Ha: p < .21

What is the only option for the null hypothesis? 

• H₀ = k
• H₀ > k
• H₀ < k
• H₀ ≠ k

Which of the following is not an option for an alternate hypothesis? 

• H_a = k
• H_a > k
• H_a < k
• H_a ≠ k

The weight of the average 6th grade student's backpack (with books in it) is 18.4 lbs. The principal of the school thinks that the backpack does not weight 18.4 lbs. What is the null and alternate hypothesis? 

• H₀ = 18.4
  H_a = 18.4
• H₀ = 18.4
  H_a > 18.4
• H₀ = 18.4
  H_a < 18.4
• H₀ = 18.4
  H_a ≠ 18.4

When do you use a t-value instead of a z-value?

• When n < 30

• When n ≥ 30

• When all of the planets align

• When the teacher says so

When do you use a t-value instead of a z-value? 

• When n < 30
• When n ≥ 30
• When all of the planets align
• When Ms. O said to