The mean number of sick days an employee takes per year is believed to be about 10. Members of a personnel department do not believe this figure. They randomly survey 8 employees. The number of sick days they took for the past year are as follows: 12; 6; 15; 3; 10; 8; 8; 8. Let X= the number of sick days they took for the past year. Should the personnel team believe that the mean number is about 10? Conduct a hypothesis test at the 5% level. What is the test statistic? (If using the z distribution round your answers to two decimal places, and if using the t distribution round your answers to three decimal places.) What is the p-value? (Round your answer to four decimal places.) Construct a 95% confidence interval for the true mean. Sketch the graph of the situation. Label the point estimate and the lower and upper bounds of the confidence interval. (Round your answers to three decimal places.)

n a city with three high schools, all the ninth graders took a Standardized Test, with these results: High School Mean score on test Number of ninth graders Glenwood 78 280 Central City 92 328 Lincoln High 73 159 The city's PR manager, who never took statistics, claimed the mean score of all ninth graders in the city was 81 . Of course, that is incorrect. What is the mean score for all ninth graders in the city? Round to one decimal place.

A marketing firm is doing research for an Internet-based company. It wants to appeal to the age group of people who spend the most money online. The company wants to know if there is a difference in the mean amount of money people spend per month on Internet purchases depending on their age bracket. The marketing firm looked at two age groups, 18-24 years and 25-30 years, and collected the data shown in the following table. Let Population 1 be the amount of money spent per month on Internet purchases by people in the 18-24 age bracket and Population 2 be the amount of money spent per month on Internet purchases by people in the 25-30 age bracket. Assume that the population variances are not the same. Internet Spending per Month 18-24 Years 25-30 Years Mean Amount Spent 55.19 65.24 Standard Deviation Sample Size 11.39 13.68 21 25 Step 1 of 2: Construct a 90 % confidence interval for the true difference between the mean amounts of money per month that people in these two age groups spend…

In a city with three high schools, all the ninth graders took a Standardized Test, with these results: High School Mean score on test Number of ninth graders Glenwood 81 261 Central City 93 338 Lincoln High 67 189 The city's PR manager, who never took statistics, claimed the mean score of all ninth graders in the city was 80.3. Of course, that is incorrect. What is the mean score for all ninth graders in the city? Round to one decimal place. mean of all ninth grader's scores =