Sampling Variability

Two samples never quite agree.

12 problems · about 21 minutes · TEKS P.S.4.C, S-IC.B.4

What this lesson teaches

The student describes sampling variability and how sample size affects it.

Straightforward practice. Get the method working first.

5 problems

Which sample gives a more reliable estimate? 1 for size 30, 2 for size 3000.
Answer 2
Why The larger one.
What is a sampling distribution?
Answer The distribution of a statistic across all possible samples.
Why How the statistic itself varies from sample to sample.
A value describing a sample is called what? 1 parameter, 2 statistic.
Answer 2
Why S for sample and statistic.
Do two random samples usually give identical statistics? 1 yes, 0 no.
Answer 0
Why Variation is expected.
Does a larger sample narrow the sampling distribution? 1 yes, 0 no.
Answer 1
Why Less variation.

The same ideas with more to keep track of.

3 problems

A sampling distribution from random samples centres on what? 1 the true parameter, 2 zero.
Answer 1
Why Randomness is unbiased.
Does increasing sample size remove bias? 1 yes, 0 no.
Answer 0
Why Bias shifts the centre.
Which is usually unknown? 1 parameter, 2 statistic.
Answer 1
Why You compute one and estimate the other.

Mixed problems. Work out what kind of question it is before you start.

4 problems

Sort each term by what it describes.
Answer Describes a population: Parameter, The true proportion in favour · Describes a sample: Statistic, The proportion in favour among 200 people asked
Why Only one of the two can actually be measured.
Population is 50% in favour. Is 70% from a sample of 10 surprising? 1 yes, 0 no.
Answer 0
Why Small samples swing widely.
The Names: A value describing a whole population is called what? 1 parameter, 2 statistic.
Answer 1
Why A parameter.
The Size: Which sample varies less? 1 for size 25, 2 for size 2500.
Answer 2
Why The larger one.