You collected times (minutes) that it takes volunteers to complete a set of pencil and paper mazes. Volunteers are randomly assigned to two groups. Group 1 watches a 5 minute video explaining good strategies for finishing the mazes. Group 2 watches a 5 minute video of other people successfully finishing the mazes, but they receive no explanation. Researchers are interested in testing against the null hypothesis there is no difference in population mean times that it takes subjects to complete mazes after watching either type of video. There are the summary statistics after collecting data. (And the sample sizes differ, because some subjects did not follow instructions correctly and so they were not included in the analysis.) x₁ = 12.88, x₂ = 8.21 s₁ = 8.06, s₂ = 7.16 n₁ = 45, n₂ = 60 a. Is this an experimental or observational study? Observational or Experimental b. What are the predictor and response variables. Are they categorical or quantitative? (You must get all correct)

Finishing time is the response variable

Finishing time is quantitative

Video type is quantitative

Video type is the predictor variable

Video type is categorical

Video type is the response variable

Finishing time is the predictor variable

Finishing time is categorical How should the null hypothesis be written?H₀: x₁ - x₂ = 5H₀: x₁ - x₂ = 0 H₀: = 0H₀: ₁ - ₂ = 5H₀: ₁ - ₂ = 0H₀: x = 5 (for the following calculations, round to 2 decimal places) c. Calculate the standard error of x₁ - x₂: d. Calculate the approximate 95% CI for ₁ - ₂: __to __

e. The result of the hypothesis test is:

We do not have evidence that there is a difference in population means, because the null value is inside the 95% CI.

We do not have evidence that there is a difference in population means, because the null value is outside the 95% CI.

We have evidence that there is a difference in population means, because the null value is inside the 95% CI.

We have evidence that there is a difference in population means, because the null value is outside the 95% CI.

f. What kind of error is it *possible* that you made?

It is possible that we made a Type I error, because this is when you reject a false null hypothesis.

It is possible that we made a Type I error, because this is when you fail to reject a false null hypothesis.

It is possible that we made a Type I error, because this is when you reject a true null hypothesis.

It is possible that we made a Type I error, because this is when you fail to reject a true null hypothesis.

It is possible that we made a Type II error, because this is when you reject a false null hypothesis.

It is possible that we made a Type II error, because this is when you fail to reject a false null hypothesis.

It is possible that we made a Type II error, because this is when you reject a true null hypothesis.

It is possible that we made a Type II error, because this is when you fail to reject a true null hypothesis.