1. A camp director is interested in the average number of letters each child sends during his/her camp session. The population standard deviation is known to be 2.5. A survey of 45 campers is taken. The average from the sample is 6.75 with a sample standard deviation of 3.1. Find the 95% confidence interval for the population mean.
What is your value for E?
What is your confidence interval?
2. An organization in 1995 (!) reported that teenagers spent an average of 5.25 hours per week on the telephone. The organization thinks that, in 2010, the average is higher. 81 randomly chosen teenagers were asked how many hours per week they spend on the telephone. The sample mean was 5.50 hours with a sample standard deviation of 2.15. At the 5% level of significance, is the organization correct?
Show your hypothesis(in Ho and Ha form).
What is your z or t score?
Is your decision to accept or not accept the null hypothesis?
3. To entice new players to the game, a publisher develops an online game that they claim can be completed in 3 hours or less. A random sample of 16 players are found and they complete the game in a mean of 3.05 hours with a standard deviation of 0.17 hours. At a 0.05 level of significance, is the publisher's claim correct?
Show your hypothesis(in Ho and Ha form).
What is your z or t score?
Is your decision to accept or not accept the null hypothesis?