5 ~ CHAPTER 9: Write the hypotheses statements. Label the claim. Identify and tailedness. 1. You are testing the mean speed of your cable Internet connection is more than 3 Megabits per second with level of significance of 10%. 2. The mean entry level salary of an employee at a company is $58,000. You believe with 95% confidence that it is higher for IT professional in the company. 3. A sociologist claims the probability that a person picked at random in Times Square in New York City is visiting the area is 0.83. You want to see if the claim is correct. 4. In a population of fish, approximately 42% are female. A test is conducted to see if, in fact, the proportion is less. Researchers use a level of significance of 0.01. Write the hypotheses statements. Label the claim. Identify , tailedness, and TEST. 5. Your statistics instructor claims that 60 percent of the students who take her Elementary Statistics class go through life feeling more enriched. For some reason that she can't quite figure out, most people don't believe her. You decide to check this out on your own. You randomly survey 64 of her past Elementary Statistics students and find that 34 feel more enriched as a result of her class. Now what do you think? 6. From generation to generation, the mean age when smokers first start smoking varies. However, the standard deviation of that age remains constant of around 2.1 years. A survey of 40 smokers of this generation was done to see if the mean starting age is at least 19. The sample mean was 18.1 with a sample standard deviation of 1.3. Do the data support the claim at the 5% level of significance? 7. Suppose an airline claims that its flights are consistently on time with an average delay of at most 15 minutes. It claims that the average delay is so consistent that the variance is no more than 150 minutes. Doubting the consistency part of this claim, a disgruntled traveler calculates the delays for his next 25 flights. The average delay for those 25 flights is 22 minutes with a standard deviation o 15 minutes. Did the passenger prove his claim? 8. An article in the San Jose Mercury News stated that students in the California state university system take 4.5 years, on average, to finish their undergraduate degrees. Suppose you believe that the mean time is longer. You conduct a survey of 49 students and obtain a sample mean of 5.1 with a sample standard deviation of 1.2. Do the data support your claim at the 1% level of significance