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Cogito

Algebra 2 · Chapter 8 · Lesson 1

Practice Worksheet

Distributions and Conditional Probability

Judging how unusual a value is.

10 problems · about 20 minutes · S-ID.A.4, S-CP.A.3, S-CP.B.6

NameDate

Figure — use these to answer the problems

Pile the marks symmetrically around the middle and you have the bell shape.
012345678910
Measured value
At 31
At 43
At 55
At 63
At 71
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

2 problems

  1. From “Infinite Geometric Series”

    First term 10, ratio 0.5. What is the infinite sum?

    Answer

  2. From “Series and Sigma Notation”

    What is the sum of 1 + 2 + ... + 50?

    Answer

Warm Up

Straightforward practice. Get the method working first.

4 problems

  1. Mean 100, standard deviation 15. About what percent lie between 85 and 115?

    Answer

  2. What does conditional probability change?

    • The pool of cases being counted.
    • Nothing.

  3. What percent lies within one standard deviation?

    Answer

  4. What percent lies within two standard deviations?

    Answer

Build It Up

The same ideas with more to keep track of.

2 problems

  1. 20 students, 8 play sport. 5 of those 8 also play music. Out of 8, how many play music?

    Answer

  2. Does conditioning on B change the denominator?

    • Yes. It becomes the B cases only.
    • No.

Stretch Yourself

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

2 problems

  1. The Range

    Mean 50, standard deviation 5. About what percent lie between 45 and 55?

    Answerpercent

  2. The Wider Range

    Mean 50, standard deviation 5. About what percent lie between 40 and 60?

    Answerpercent