Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

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

The six worst estimates are shown in pink on the stem and leaf plot:

These six estimates are the most different from 500. Specifically, they differ from 500 by more than 100; they are either less than 400 or greater than 600.

The other 94 estimates differ from 500 by 100 or less. These 94 estimates fall between 400 and 600, inclusive.

We'll refer to these inclusive ranges of values as intervals, and use such intervals to classify the estimates:

 • Ninety-four of 100 (94/100) estimates fall between 400 and 600 (inclusive). • Six of 100 (6/100) estimates fall outside of this interval.

Problem C3

 a. What proportion of the estimates are 75 or fewer penguins away from the actual value? b. What proportion of the estimates are more than 75 penguins away from the actual value?

Problem C4

Use this stem and leaf plot to complete the table below:

Interval (inclusive)

Proportion of Estimates in Interval

Proportion of Estimates Not in Interval

 350-650 375-625 400-600 94/100 6/100 425-575 84/100 16/100 450-550 475-525

Interval (inclusive)

Proportion of Estimates in Interval

Proportion of Estimates Not in Interval

 350 - 650 100/100 0/100 375 - 625 98/100 2/100 400 - 600 94/100 6/100 425 - 575 84/100 16/100 450 - 550 69/100 31/100 475 - 525 37/100 63/100