PROBLEM 1

Among US Households, only 20% have a landline phone.A telemarketing campaign will involve a SRS of 2000 households.LetXbe thenumberof households that have a landline phone among the 2000 households randomly chosen.

What is the mean ofX?

What was the standard deviation ofX?

Note: the correction factor can be ignored in this case

AssumingXis approximately normal, find P(X>300).

PROBLEM 2

A supplier of ballpoint pens guarantees a low defective rate.Sara receives a shipment of 500 pens (and unknown to Sara, but known to you, exactly 13 are defective).Sara decides to randomly check 100 pens.LetXbe thenumberof defectives Sara finds among the 100 randomly selected pens.

The possible values ofXare whole numbers ranging from _____ to _____.

What is the mean ofX?

What was the standard deviation ofX?

Hint: you need the correction factor