Lab Assignment on Confidence Intervals

Instructions: Answer each of the following questions and include screenshots of your handwritten work to support your answers. Your final submission should be a Word doc or a pdf. The questions should be done with a group of 2-3 other students. List their names and a description of their contribution at the end of the document.

1. We begin by looking at the prototypical confidence interval (CI):

Using the context of the heights of PLNU undergraduates, write a one sentence description for each of if and. Based on your work in Lab 5, write a similar description.

2. Repeat parts 4 and 5 above to compute 90% and 99% CI’s for the sample of heights of 74 PLNU undergraduates (with the same is66.8). Write an additional sentence or two to compare the effect of changing the confidence level down to 90% or up to 99%.

3. Go back to a 95% confidence level (with the same 66.8) and repeat parts 4 and 5 above in the case that the sample size is reduced by half, where it is doubled, and where it is quadrupled. Write an additional sentence or two to compare the effect of changing the sample size up and down.

4. Do not forget to compare your answers to the previous questions. List the names of your group and give a brief description of their contribution at the end of the document.

5. Use step 4 of example 16.1 in the textbook on page 377 to write a sentence that explains what your confidence interval means in the context of the heights of PLNU undergraduates. Because we got the interval to from a method that captures the population mean for 95% of all possible samples, we say that we are 95% confident that the mean of all is some value in the interval, no lower than and no higher than.