MATH 1P98 - Assignment #2 Due: Wednesday, June 8, 2016 @ 19:00 Assignments must have a cover page (refer to the course outline). Please write on one side of the page only and show ALL your work. Answer questions with sentences. Include any printout for a question with the question and clearly label the printout with the question number and part. Keep three decimal places. 1) The following table shows the number of spam e-mails that arrive in my inbox each day. Number of Spam EMails Frequency 3 10 4 29 5 28 6 42 7 16 a). What is the probability for the number of spam e-mails received per day? b). What is the mean of the probability distribution? c). What is the standard deviation of the probability distribution? 2) According to the National Work Intensification Survey, 42% of Americans felt their workload last year had significant more responsibility when compared to the start of the recession in December 2007. A random sample of five working Americans was selected. What is the probability that more than three of them felt their workload in 2011 had significant more responsibility when compared to the start of the recession in December 2007. 3) According to a Rasmussen Report survey, 4% of adults indicated that coffee ice cream was their favorite flavor. A random sample of 21 adults was selected. Use the Poisson distribution to approximate the binomial distribution to determine the probability that more than two adults from this sample would choose coffee ice cream as their favorite flavor. 4) According to the Labor Department, the average duration of unemployment for adults ages 20 to 24 was 34.6 weeks during a recent month. Assume that the standard deviation for this population is 10.2 weeks. A random sample of 36 adults in this age group was selected. What is the probability that the average duration of unemployment was between 31 and 35 weeks? 5) The average battery life of the iPhone 4S is reported to be 6.0 hours by Apple. Assume that the standard deviation for the battery life for this cell phone is 30 minutes. A random sample of 50 iPhones had an average battery life of 5.7 hours. Use a 90% Page 1 of 2 confidence interval to test the validity of Apple's claim. 6) The following table shows the wait time on the phone, in minutes, of six individuals who require assistance from a customer service representative. Determine the 90% confidence interval for this sample. 7) A survey by Harris Interactive reported that 35% of college students prefer digital textbooks over traditional print textbooks. State University would like to confirm these results. A random sample of 125 students was asked their textbook preference and a total of 37 preferred the digital format. Use a 95% confidence interval to validate the Harris Interactive findings. Page 2 of 2