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Data Session 9, Part C: Investigating Variation in Estimates
 
Session 9 Part A Part B Part C Part D Homework
 
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Session 9, Part C:
Investigating Variation in Estimates

In This Part: Using a Stem and Leaf Plot | Judging the Quality of Estimates | Intervals
Describing Intervals | Probabilities

These six intervals provide a description of how widely the estimates vary from sample to sample, and how close the estimates are to the actual value of 500: Note 6

Interval

Interval Range

Interval Radius

Proportion of Estimates in Interval

350-650

300

150

100/100

375-625

250

125

98/100

400-600

200

100

94/100

425-575

150

75

84/100

450-550

100

50

69/100

475-525

50

25

37/100

The interval from 350 to 650 is the largest interval in the table above; its interval range is 300. This tells us two things:

 

All (100/100) of the estimates are between 350 and 650, a range of 300.

 

These estimates fall within 150 (the interval radius) of 500.

The interval 475 to 525 is the smallest interval in the table. This tells us two things:

 

Fewer than half (37/100) of the estimates are between 475 and 525, a range of 50.

 

These estimates fall within 25 (the interval radius) of 500.


 

Problem C5

Solution  

a. 

Explain why it is useful for the proportion of estimates in an interval to be high.

b. 

Explain why it is useful for the interval range to be small.

c. 

What happens to the proportion of estimates in the interval as the interval range decreases?


Next > Part C (Continued): Probabilities

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