Do students tend to improve their SAT mathematics (SAT-M) score the second time they take the test? A random sample of four students who took the test twice received the following scores. Student 1 2 3 4 First Score 450 520 720 600 Second Score 440 600 720 630 Assuming that the change in SAT-M score (second score – first score) for the population of all students taking the test twice is Normally distributed with mean μ, a 95% confidence interval of μ is (hint: use Excel)

Answer this question only if you know the 30 points and

The krasnapolski is a top-of-the-line hotel in amsterdam, the netherlands. among their many services, they rent bicycles to guests. the bicycle checkout is open 24 hours per day 7 days per week and has 50 bicycles on hand. on average, 10 guests request a bicycle each day, arriving completely randomly at all times of the day during the spring and summer seasons. guests keep bicycles for four days on average, with a standard deviation of two days. how long does a guest on average have to wait for a bike? a. approximately 24 hours b. approximately 0.033 hours c. approximately 4 days d. approximately 47 minutes

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.