What a sample can tell you about a population.
The final topic of the course, and the reason for everything in the probability strand. You cannot survey everyone, so you survey some and estimate the rest. These lessons cover how to sample fairly, how much samples vary, and how to turn a single sample into a statement about the whole population with a stated level of confidence.
Lesson 1
Random Sampling
Populations and samples, parameters and statistics, the four probability sampling methods, the five sources of bias, and the natural variability between fair samples. Twenty practice questions, ten harder ones, and a ClassPad guide.
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The Sampling Distribution of p̂
The sample proportion as a random variable, its mean and standard deviation, when it is approximately normal, and using a point estimate when p is unknown. Twenty practice questions, ten harder ones, and a ClassPad guide.
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Confidence Intervals
Interval estimates for a proportion, constructing and interpreting them, and what a confidence interval does and does not mean. Twenty practice questions, ten harder ones, and a ClassPad guide.
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Margin of Error & Sample Size
What controls the width of an interval, the trade-off between confidence and precision, choosing a sample size, and why 0.5 is used when nothing is known about p. Twenty practice questions, ten harder ones, and a ClassPad guide.
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