Probability and Percentiles with TI-84

This video tutorial demonstrates how to use the TI-84 calculator to determine probabilities and percentiles from a distribution of sums. It covers calculating the mean and standard deviation for the sum of ages of tablet users, using the central limit theorem to assume a normal distribution, and finding specific probabilities and percentiles using the normal cdf and inverse norm functions on the TI-84.

What is the mean age of tablet users according to the study?

• 35 years

• 33 years

• 31 years

• 29 years

How do you calculate the mean of the sum of ages?

• Mean divided by the sample size

• Sample size times the mean

• Sample size divided by the mean

• Mean plus the sample size

What is the formula for the standard deviation of the sum of ages?

• Sample size times the standard deviation

• Square root of the sample size times the standard deviation

• Square root of the standard deviation times the sample size

• Standard deviation divided by the sample size

Which function on the TI-84 is used to find the probability of a sum of ages within a range?

• Normal CDF

• Normal PDF

• Standard Deviation

• Inverse Norm

What is the probability that the sum of ages is between 1400 and 1600 years?

• 50.00%

• 77.48%

• 25.00%

• 11.93%

What is the probability that the sum of ages is more than 1625 years?

• 25.00%

• 77.48%

• 11.93%

• 50.00%

What is the upper bound used for calculating the probability of exceeding 1625 years?

• 999999

• 1000

• 2000

• 5000

What does the 75th percentile represent in this context?

• The average sum of all ages

• The sum that is less than 75% of other sums

• The median sum of all ages

• The sum that is greater than 75% of other sums

Which function on the TI-84 is used to find the 75th percentile?

• Normal CDF

• Normal PDF

• Standard Deviation

• Inverse Norm

What is the 75th percentile for the sum of ages?

• 1550.0 years

• 1592.9 years

• 1600.0 years

• 1625.0 years