Statistic Calculation Problem

You may discuss this lab with your classmates, but your writeup should be done by yourself. Your name MUST be typed into the Excel spreadsheet (not handwritten on a printout).

The example shown below does not use the actual data set. The real assignment is at the end.

In this example, an item has been purchased from 10 different retail shops. We wish to test the hypothesis that the population mean price is greater than 3 dollars. The screen capture shown below shows the formu- las that were entered into column E to generate the numbers that you see there.

The first three entries just calculate n, x , and s. The next entry is the standard error, which is the name of

the quantity s

n that is used in the denominator of the test statistic.

The entry next to “mu zero” should be the value that would appear in the null hypothesis. Since we are test- ing to see if the population mean is greater than 3, our null hypothesis would have been H0: 3  , so the number “3” appears there. Next to the word “tails”, you would enter “1” for either the upper or lower 1- sided test, or “2” for a 2-sided test.

The p-value is found using the Excel function called TDIST. This function requires 3 pieces of information. The first item is the absolute value of the test statistic. The second item is the number of degrees of free- dom, and the final item tells the function whether or not to double the area under the curve. The TDIST function then finds the area under the curve, to the right of the absolute value of the test statistic, and dou- bles that area for 2-sided tests.

Lab 1: Hypothesis Tests Stat 244 Spring 2021 Due April 21

Lab 1 (Due April 21)

Using the method described above, and the data set called “gas2015.xlsx”, test to see if there is evidence that the population mean price for a gallon of gas differs from $2.50. Use 0.05.  Include this file with your test results in your assignment submission.

Include a full 5 Step writeup. While Excel will be used to perform calculations for Step 3 (you can just de- clare your p-value and compare it to your alpha), you must still write Steps 1, 2, 4, and 5. I encourage you to hand-write these steps and scan the file as a pdf.

Include both the .xlsx file (with your test results) and your 5 Step writeup in your D2L submission. Your submission will thus be made up of two different files – do not merge these together into a single file.