According to a 2012 report, 67.8 % of all US adults still have a landline telephone service for which they pay.Given the rise of cell phone use, an employee for a local telephone company is interested in seeing if this percentage has decreased.A random sample of 428 US adults is selected from 2014 tax returns.Each person sampled is asked if still have a landline telephone service for which they pay.

1. What sampling frame was used in this example?

• 2014 tax returns
• 2014 deeds
• 2014 driver's license records
• 428 adults

1. What conjecture has been made by the local telephone company?

• The proportion of individuals with a landline telephone service is 0.678.
• The proportion of individuals with a landline telephone service has increased.
• The proportion of individuals with a landline telephone service has decreased.

1. Completely describethe sampling distribution for the sample proportion of US adults who have a landline telephone service for which they pay when samples of size 428 are selected (assuming there has been no change from 2012).Round any calculated value to four decimal places.

• mean:
• p
• p^
• =
• standard deviation:
• p
• p^
• =
• shape: the distribution of
• p
• p^
• isSelect an answer
• not normally distributed.
• normally distributed.
• Checks: np =and n(1 - p) =

1. When the sample of 428 adults is selected, it is found that 275 still have landline telephone service. What is thesample proportionof individuals who still have landline telephone service? Round your answer to four decimal places.
2. p
3. p^

• p
• p^
• =

1. Using the distribution described in part c, what is theprobabilityof observing 275 or fewer adults with landline telephone service in this sample?

• z =(round to 2 decimal places)
• probability =(round to 4 decimal places)

1. Based on the data collected from the sample, what conclusion can be drawn?

• Because the probability isSelect an answer
• small
• large
• , thereSelect an answer
• is not
• is
• significant evidence to support the conjecture that the use of landline telephones has decreased from 67.8%.