×
×

# In Exercises, assume that 400 births are randomly ISBN: 9780321836960 18

## Solution for problem 9BSC Chapter 4.2

Elementary Statistics | 12th Edition

• Textbook Solutions
• 2901 Step-by-step solutions solved by professors and subject experts
• Get 24/7 help from StudySoup virtual teaching assistants Elementary Statistics | 12th Edition

4 5 1 322 Reviews
11
2
Problem 9BSC

In Exercises, assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that the result is far from what is typically expected.

Exactly 205 girls.

Step-by-Step Solution:

Step 1 of 5</p>

you have to consider that there are so many possibilities from 0 girls to 400 girls. of course (assuming boys/girls are equally likely), around 200 girls will be the highest probability zone, but "exactly" 205 makes it unlikely.

Step 2 of 5</p>

Random Variable: X = # of girls in 400 births.

X is a Binomial Random Variable. Normal Approximation to Binomial?.

Assume p = 0.5; n = 400; q = 0.5.

n.p = n.q = 200 ≥ 5. (It is Ok to use the Normal approximation)

Step 3 of 5</p>

Find µ and σ for the Normal distribution.

For a Binomial Random Variable:

µ = n.p = 400(0.5)=200

σ = = = 100

Step 4 of 5

Step 5 of 5

##### ISBN: 9780321836960

Unlock Textbook Solution