The field of statistics uses a number called the probability value (“p-value”) to describe the percentage likelihood that the results of a research study occurred by chance. Ronald A. Thisted, a professor of statistics at the University of Chicago, describes the p-value as a number that “measures consistency between the results actually obtained in the trial and the ‘pure chance’ explanation for those results.” The TI-83, a graphing calculator manufactured by Texas Instruments, is capable of calculating the p-value for a normal distribution, student’s t-distribution and chi-square distribution.

### Step 1

Press the “On” button.

### Step 2

Press the button labeled “2nd” and then the button labeled “VARS” to access the distribution menu.

### Step 3

Press the number “2” to select the second option on the menu, “normalcdf,“ to calculate the p-value of a normal distribution. Press the number “5” to select the fifth option on the menu, “tcdf,“ to calculate the p-value for a student’s t-distribution. Press the number “7” to select the seventh option on the menu, “X^2cdf,” to calculate the p-value for a chi-square distribution.

### Step 4

Enter the lower bound of the data set.

### Step 5

Insert a comma.

### Step 6

Enter the upper bound of the data set.

### Step 7

Insert a comma.

### Step 8

Enter the mean of the data set.

### Step 9

Insert a comma.

### Step 10

Enter the standard of deviation of the data set.

### Step 11

Press “Enter.”