Reference no: EM131887133

1.) USA Today reported 80% of adult drivers admit that they often talk on the cell phone while driving. This estimate was based on data from a sample of 1010 adult drivers.  Construct a 90% confidence interval for the population proportion of adult drivers that admit they talk on cell phones while driving.

2.)  Seven students visiting the student health center for a free dental examination during National Dental Hygiene Month were asked how many months had passed since their last visit to the dentist. Their responses were : 6, 9, 11, 22, 19, 14, 25. Find the 95% confidence interval of the true mean number of months elapsed since the last visit to a dentist for the population of students participating in the program.

3.) Explain the difference between a Type 1 error and a Type 2 error. Give a real world example of each and the consequences of making such an error.

4.) An educator claims that the average salary of substitute teachers in school districts in NC earn less than $92 per day. A random sample of twelve districts is selected, and the daily salaries are given below. With α = 0.05, is there enough evidence to support the claim?

85       95       90       90       110     100     75       80       70       100     90       85

5.) What motivates companies to offer stock ownership plans to their employees? In a random sample of 117 companies having such plans, 64 said that the primary rationale was tax related. Does this information provide strong support for concluding that more than half of the all such firms feel this way? Let α = 0.01