PreparED Study Materials
Videos
Testing the 123-Gallon Daily Water Claim: Fact or Fiction?
Want To Learn More? To watch the entire video and ALL of the videos in the series:
full solution
Explore the claim that average daily water consumption is 123 gallons. Using statistical testing, we evaluate a new sample against the Old Farmer’s Almanac claim. Learn how to interpret p-values and t-scores in hypothesis testing.
Analyzing Salad Habits: A Statistical Look at 85.5%
Want To Learn More? To watch the entire video and ALL of the videos in the series:
full solution
Examine a survey of 200 adults regarding salad consumption, leading to a sample proportion of 85.5%. Using hypothesis testing and z-test calculations, the video determines whether more than 85% of American adults eat salad weekly. The results offer statistical insights into dietary habits.
Eye Color & Assortative Mating in Scandinavian Couples
Want To Learn More? To watch the entire video and ALL of the videos in the series:
full solution
Explore the concept of assortative mating through an eye-color study of 204 Scandinavian couples. Discover how probabilities highlight nonrandom mating patterns. Conclude if eye colors of partners are independent or reveal assortative tendencies.
Analyzing Age Distribution of Proofreaders: A Statistical Approach
Want To Learn More? To watch the entire video and ALL of the videos in the series:
full solution
Discover the statistical process behind analyzing the age distribution of proofreaders at a publishing company. Learn how to use the Z-score formula for individual and sample mean probabilities, and how to interpret results using a Z-table.
Battery Lifetimes: Mean, Variance & Standard Deviation
Want To Learn More? To watch the entire video and ALL of the videos in the series:
full solution
Discover the nuances of analyzing battery lifetime data through mean, variance, and standard deviation computations. Using class boundaries, midpoints, and frequencies, gain insights into the dispersion of battery lifespans and the average deviation from the mean.
Thread Strength After Heat Treatment: A 99% Confidence Analysis"
Want To Learn More? To watch the entire video and ALL of the videos in the series:
full solution
Explore the impact of heat treatment duration on thread breaking strength. Using statistical analysis, we assess the difference in mean strengths between batches. Confidence intervals help quantify this difference with 99% certainty.



















