Exploring Probabilities in Normal Distribution with TI-84

This video tutorial demonstrates how to calculate probabilities for normally distributed data using the TI-84 family of graphing calculators. It covers the calculation of probabilities for utility bills in a city with a given mean and standard deviation. The tutorial explains how to find the probability of bills being less than $85, between $90 and $120, and more than $130, using the normal cumulative distribution function (CDF) on the calculator. The video emphasizes the efficiency of using a calculator over traditional table methods.

What is the mean of the monthly utility bills in the given problem?

• $130

• $90

• $85

• $110

What is the standard deviation of the monthly utility bills in the given problem?

• $10

• $20

• $13

• $15

Which calculator model is specifically mentioned in the video?

• TI-84 Plus Color Edition

• TI-83 Plus

• TI-Nspire CX

• TI-89 Titanium

What is the first step in finding the probability that a utility bill is less than $85?

• Use the normal PDF function

• Draw a picture

• Calculate the mean

• Convert to z-scores

What command is used on the TI-84 calculator to find cumulative probabilities?

• invNorm

• normal CDF

• binomCDF

• normal PDF

What is the approximate probability of selecting a utility bill less than $85?

• 0.0272

• 0.0513

• 0.0712

• 0.0619

What is the lower limit when finding the probability between $90 and $120?

• 85

• 90

• 110

• 120

What is the approximate probability of selecting a utility bill between $90 and $120?

• 0.0619

• 0.0513

• 0.7172

• 0.0272

What is the upper limit when finding the probability of a utility bill more than $130?

• 120

• 90

• 1e99

• 85

What is the approximate probability of selecting a utility bill more than $130?

• 0.0513

• 0.7172

• 0.0619

• 0.0272