Sampling Variability

Two samples never quite agree.

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

NameDate

Figure — use these to answer the problems

Bunch the values tightly and the box narrows. A larger sample narrows a sampling distribution the same way.

Sample 19

Sample 210

Sample 310

Sample 411

Sample 512

Figure 1

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
What is a sampling distribution?
- The distribution of a statistic across all possible samples.
- The distribution of the data in one sample.
A value describing a sample is called what? 1 parameter, 2 statistic.
Answer
Do two random samples usually give identical statistics? 1 yes, 0 no.
Answer
Does a larger sample narrow the sampling distribution? 1 yes, 0 no.
Answer

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
Does increasing sample size remove bias? 1 yes, 0 no.
Answer
Which is usually unknown? 1 parameter, 2 statistic.
Answer

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

4 problems

Sort each term by what it describes.
Write each item under the heading it belongs to: Parameter · The true proportion in favour · Statistic · The proportion in favour among 200 people asked
Describes a population
Describes a sample
Population is 50% in favour. Is 70% from a sample of 10 surprising? 1 yes, 0 no.
Answer
The Names
A value describing a whole population is called what? 1 parameter, 2 statistic.
Answer
The Size
Which sample varies less? 1 for size 25, 2 for size 2500.
Answer