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Ch.10: Sampling Distributions: ProportionWorksheetSee all chapters
All Chapters
Ch.1: Displaying Numeric Data
Ch.2: Measures of Center and Spread
Ch.3: Probability and Rules
Ch.4: The Discrete Random Variable
Ch.5: The Binomial Random Variable
Ch.6: Types of Continuous Random Variable Distributions
Ch.7: The Standard Normal Distribution (Z-Scores)
Ch.8: Using The Z-Score
Ch.9: Sampling Distributions: Mean
Ch.10: Sampling Distributions: Proportion
Ch.11: Hypothesis Testing: Part 1
Ch.12: Hypothesis Testing: Part 2

Concept #1: Calculating the Minimum Sample Size Needed

Concept #2: Calculating the Minimum Sample Size Needed: Intro

Practice: A previous study found that your school consists of 60% White/Caucasian students. You want the 98% confidence interval for the proportion of White/Caucasian students to be no more than .05 away from the true proportion. How many students must you sample to create this confidence interval?

Practice: Rain in Florida is heavy during the spring. Assume that the standard deviation of average daily rainfall for the Spring is 8 inches. If you want to construct a 90% confidence interval to be within 2 inches of the true average rainfall in Florida, how many days need to be sampled?

Practice: It's said that most people prefer the color red. Your company has asked you to estimate the percent of people who prefer the color for manufacturing purposes. Construct a 95% confidence interval, but the company wants you to be within .01 of the population proportion.

Practice: You think you have a lot of speeding tickets so you decide to construct a 97% confidence interval for the average number of speeding tickets people your age receive. Assuming that the standard deviation is 10 tickets and that you want to be no more than 1 ticket away from the true average, how many random people do you need to sample?