Cogito
Integrated Math 3 · Chapter 7 · Lesson 1
Sampling and Sampling Variability
Why two samples never agree.
12 problems · about 21 minutes · S-IC.A.1, S-IC.B.4
Figure — use these to answer the problems
- Minimum9
- Lower quartile9.50
- Median10
- Upper quartile11.50
- Maximum12
- Interquartile range2
Warm Up
Straightforward practice. Get the method working first.
5 problemsWhich sample gives a more reliable estimate? 1 for size 30, 2 for size 3000.
AnswerWhy does a larger sample not fix bias?
- Bias is systematic, so more data repeats the same error.
- Because large samples cost too much.
A value describing a sample. 1 parameter, 2 statistic.
AnswerDo two random samples usually give identical statistics? 1 yes, 0 no.
AnswerWhich sample varies less? 1 for size 25, 2 for size 2500.
Answer
Build It Up
The same ideas with more to keep track of.
3 problemsAn online poll where readers choose to respond. Biased? 1 yes, 0 no.
AnswerWhich is usually unknown? 1 parameter, 2 statistic.
AnswerWhich matters more for accuracy? 1 method, 2 size.
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
4 problemsSort each term by what it describes.
Write each item under the heading it belongs to: Parameter · The true proportion in favour · Statistic · The proportion among 200 people asked
Describes a population
Describes a sample
Population 50% in favour. Is 70% from a sample of 10 surprising? 1 yes, 0 no.
AnswerThe Name
A value describing a whole population. 1 parameter, 2 statistic.
AnswerThe Size
Does a larger sample fix bias? 1 yes, 0 no.
Answer