According to a 2012 report, 68.8 % 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 439 US adults is selected from 2014 driver's license records. Each person sampled is asked if still have a landline telephone service for which they pay.

What sampling frame was used in this example?

a. 2014 drivers license

b. 439 adults

c. 2014 tax returns

d. 2014 deeds

What conjecture has been made by the local telephone company?

a. the proportion of individuals with a landline telephone has increased

b. the proportion of individuals with a landline telephone has decreased

c. the proportion of individuals with a landline telephone service is 0.688

1. Completely describe the sampling distribution for the sample proportion of US adults who have a landline telephone service for which they pay when samples of size 439 are selected (assuming there has been no change from 2012).Round any calculated value to four decimal places.
   • mean: p^ =_______?
   • standard deviation: p^ = ________?
   • shape: the distribution of p^is Select an answer? (normally distributed / not normally distributed.)
     • Checks: np = __________?and n (1 - p) = __________?
2. When the sample of 439 adults is selected, it is found that 283 still have landline telephone service. What is the sample proportion of individuals who still have landline telephone service? Round your answer to four decimal places. pp^

0p^ = ______________?

1. Using the distribution described in part c, what is the probability of observing 283 or fewer adults with landline telephone service in this sample?
   • z = ________? (round to 2 decimal places)
   • probability = _______? round to 4 decimal places)

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

• Because the probability is Select an answer? (small /large), there Select an answer? (is / is not) significant evidence to support the conjecture that the use of landline telephones has decreased from 68.8%.