# Calculator Tips

In this post, I will go through a few of the functions in the two recommended calculators (TI-36X and the TI-83 / 84), including links to videos on how to use the various functions. In most cases I found YouTube videos to help, but in some cases I didn’t find any good ones. Please practice using your own calculator, especially while attempting the practice problems from the review packet!

## 1-Var Stats (Mean / Standard Deviation)

This function is used to calculate the mean, standard deviation, and the quartiles / 5-number summary (Low, Q1, Med, Q3, High) of a data set.

The same function can be used to calculate the expected value (mean) and standard deviation of a probability distribution. See the following video for a TI-83 / 84:

Unfortunately, I don’t see a good video tutorial for a TI-36X in this case, but the idea is simple: input the data in L1, and the probabilities in L2, and then when you click 1-Var Stats, click L1 for DATA and L2 for FRQ.

## normalcdf

TI-36X: On a TI-36X, I didn’t find a good video, but you can find the function normalcdf under 2nd [stat-reg/distr], menu item 2. Enter in the lower bound (-10^99 if you do not have one), upper bound (10^99 if you do not have one), the mean and standard deviation.

TI-83/84normalcdf(lower, upper, mu, sigma)

## invNorm

Suppose we have a normal distribution, with mean $\mu$, and standard deviation $\sigma$, and that we are given a probability p (perhaps as a percentage, or as a decimal). Then $invNorm(p, \mu, \sigma)$ gives us the x-value so that the probability of being less than that x value in the normal curve is exactly p.

TI-36X: Find invNorm under the 2nd [stat-reg / distr] menu, item number 3. Provide the probability under area, the mean under mu, and the standard deviation under sigma.

TI-83/84: invNorm(p, mu, sigma)