Understanding Normal Distribution and TI-84 Calculations

This video tutorial demonstrates how to use the TI-84 graphing calculator to find a data value given a probability in a normal distribution. The example involves a class exam with a normal distribution of scores, a mean of 82, and a standard deviation of 5. The goal is to determine the test score C such that 25% of students score above it. The tutorial explains how to model the distribution, use the inverse norm feature on the TI-84, and calculate the value of C. It also covers the concept of percentiles, illustrating that the 75th percentile corresponds to a score of 85.4.

What is the mean score of the exam mentioned in the video?

• 87

• 80

• 85

• 82

What is the standard deviation of the exam scores?

• 3

• 4

• 6

• 5

What is the probability of a student scoring above the test score C?

• 75%

• 25%

• 10%

• 50%

Which feature of the TI-84 calculator is used to find the test score C?

• Normal CDF

• Inverse Norm

• Normal PDF

• Standard Deviation

What probability must be entered into the TI-84 to find the value of C?

• 0.25

• 0.50

• 1.00

• 0.75

What is the approximate value of C calculated using the TI-84?

• 84.5

• 82.0

• 85.4

• 87.0

What percentage of scores are below the calculated value of C?

• 100%

• 75%

• 50%

• 25%

What is a percentile?

• A measure of central tendency

• A measure of variability

• A measure indicating the value below which a percentage of observations fall

• A measure of skewness

What percentile corresponds to the test score of 85.4?

• 50th

• 60th

• 75th

• 90th

If 75% of scores fall below a certain value, what is this value called?

• Mean

• Median

• 75th Percentile

• Mode