Lessons 6.3 - 6.4 Practice (due 3/18)

Lesson 6.3:

Interpret the standard deviation from #1:

Make sure to check your notes.

I will grade this question by hand.

Lesson 6.3

Would it be appropriate to use a normal distribution to model the sampling distribution

of Y = the number of Labs with dysplasia in the sample?

Check the Large Counts Condition.

Justify your answer.

Select the four answers that explain.

Lesson 6.3:

In a congressional district, 55% of registered voters are Democrats. A polling organization selects a random sample of 500 registered voters from this district.

Let x= the proportion of Democrats in the sample.

Would it be appropriate to use the Normal Distribution with the above situation?

Hint: is the Large Counts Condition met?

Select the four answers that explain.

Lesson 6.3:

A USA Today poll asked a random sample of 1012 U.S. adults what they do with the milk in their cereal bowl after they have eaten.

Let p-hat be the proportion of people in the sample who drink the cereal milk.

A spokesman for the dairy industry claims that 70% of all U.S. adults drink the cereal milk. Suppose this claim is true.

Would it be appropriate to use the Normal Distribution with the above situation?

Hint: is the Large Counts Condition met?

Select the four answers that explain.

Lesson 6.4:

Interpret the Sampling Distribution Standard Deviation of beak depths below:

(I will grade this myself)

Lesson 6.4:

How large would the sample size need to be to have a standard deviation of 0.25 instead of 0.316 for the sampling distribution of sample means for beak depth?

Remember, the population standard deviation = 1.0 mm.

Use the standard deviation formula, set it up to solve for the sample size (n).

** Use your algebra skills to solve for n!!

Lesson 6.4:

How large of a sample size would be needed to decrease the standard deviation from 2.899 to 1.5 for battery lifetime?

Remember the population standard deviation = 8.2 months.

Set up the formula for the standard deviation, use your algebra skills to solve for n!

Round to the nearest whole.