8 of 13 - /12 . . . WN - View Policies Current Attempt in Progress Number of Text Messages a Day A random sample of n = 755 US cell phone users age 18 and older in May 2011 found that the average number of text messages sent or received per day is 41.5 messages, with standard error about 6.1. 1Smith, A., "Americans and Text Messaging," Pew Research Center, http://www.pewinternet.org/Reports/2011/Cell- Phone-Texting-2011/Main-Report/How- Americans-Use-Text-Messaging.aspx, accessed September 19, 2011. Part 170f13 -/2 ;= Q We are 95 % sure that the condence interval for the proportion believing a car is a necessity is between 0.83 and 0.89. Q We are 95 % sure that the proportion of all adults in the US who think a car is a necessity is between 0.83 and 0.89. 1Taylor, P. and Wang, W., "The Fading Glory of the Television and Telephone," Pew Research Center, http://pewsocialtrends.org/pu bs/762/fading glorytelevisiontelephoneluxury necessity#prcjump, accessed August 19, 2010. 10f13 ) I '\\ A N NI 0.. View Policies Current Attempt in Progress College Graduates 27.5 % of US adults are college graduates. Click here to access StatKey. Round your answers to three decimal places. (a) Use StatKey or other technology to generate a sampling distribution for the sample proportion of college graduates using a sample size ofn = 50. Generate at least 1000 sample proportions. Give the center of the sampling distribution and give the standard error. Center = @dard error = 8 of 13 - /12 E . . . Question Part Score --/6 Part 2 (b) Find a 95 % confidence interval for the mean number of text messages. The 95 % confidence interval is to H.7 of 13 -12 E . . . View Policies Current Attempt in Progress Is a Car a Necessity? A random sample of n = 1483 adults in the US were asked whether they consider a car a necessity or a luxury, and we find that a 95 % confidence interval for the proportion saying that it is a necessity is 0.83 to 0.89. Explain the meaning of this confidence interval in the appropriate context. 95 % of all adults believe a car is a necessity, with probability 0.83 to 0.89. O We are 95 % sure that between 0.83 and 0.89 of the 1483 adults in the survey believe that a car is a necessity. O We are 95 % sure that the confidence interval for the proportion believing a car is a necessity is between 0.83 and 0.89. O We are 95 % sure that the proportion of all adults in the US10f13 > -/12 25 Center = Standard error = (b) Repeat part (a) using a sample size of n = 500. Center = Standard error =