A librarian believes that most books are kept longer or shorter than the allowed time of 3 weeks. What is the alternative hypothesis?(THE AVERAGE TIME A BOOK IS KEPT 3WEEKS,  IS DIFFERENT FROM 3,  WEEKS, LONGER THEN 3 WEEKS) What is the null hypothesis?( AVERAGE TIME KEPT, DIFFERENT OR  LONGER_

81% of students say that they do not get enough sleep

Please help me fast

If you roll a 6-sided die 6 times, what is the best prediction possible for the number of times you will roll an even number? times

Linda is in her first semester at a university and is taking a calculus course with a large enrollment. She just took the first midterm exam and is nervous about her score, which was 68. Among all the students in the course, the mean of the exam was 79 with a standard deviation of 15. Find the =-score of Linda's exam score relative to the exam scores among all the students in the course. Round your answer to two decimal places.

What is the probability that more than 4 accidents will occur within any given year at an intersection, where the mean number of accidents at the intersection per year is 3? what is the probability that more than 3 accidents will occur within any given year at the intersection? Give answer to 3 decimal places.

O Macmillan Learning In 2017, the entire fleet of light-duty vehicles sold in the United States by each manufacturer must emit an average of no more than 86 milligrams per mile (mg/mi) of nitrogen oxides (NOX) and nonmethane organic gas (NMOG) over the useful life ( 150,000 miles of driving) of the vehicle. NOX + NMOG emissions over the useful life for one car model vary Normally with mean 82 mg/mi and standard deviation 5 mg/mi. A company has 25 cars of this model in its fleet. What is the probability that the average NOX + NMOG level of these cars is above 86 mg/mi? Give your answer to four decimal places. probability: MacBook Air

Just solve part b please

The probability of relapse into alcoholism can be modeled with a discrete random variable with mean ? = 4 years. Find the probability that a person will not reoffend in the first 2 years.

Suppose that we doubled everyone's original salary what will happen to the mean and sd