Njcu uses thousands of brightlight fluorescent light bulbs each year. a new manufacturer, lightlight, claims that its new brand of bulbs, which cost the same as the brand njcu currently uses, has a mean life of 6000 hours. the university has never studied how long brightlight bulbs last and they decided they’re curious to see how long lightlight bulbs last compared to lightlight bulbs. njcu decides to conduct a significance test at the .05 significance level. 64 bright light bulbs are tested and the mean life time is found to be 5910 hours. both manufacturers report that the standard deviation for the lifespan of light is 400 hours.

what is the type, mean and standard deviation of the sampling distribution under the null hypothesis?
what is the value of the sample mean?

Write the following as a base and exponent

Aswimming pool had 2.5 million liters of water in it. some water evaporated, and then the pool only had 22 million liters of water in it. what percent of the water evaporated?

Suppose we have a set of small wooden blocks showing the 26 letters of the english alphabet, one letter per block. (think of scrabble tiles.) our set includes 10 copies of each letter. we place them into a bag and draw out one block at a time. (a) if we line up the letters on a rack as we draw them, how different ways coukl we fill a rack of 5 letters? (b) now suppose we just toss our chosen blocks into a pile, and whenever we draw a letter we already have, we put it back in the bag and draw again. how many different piles of 5 blocks could result? possible? piles will contain at least one repeated letter? (c) if we draw out 5 blocks wit hout looking at them, how many different piles are (d) if we draw out 5 blocks without looking at them, how many of the possible 2. (4) consider the following formula. 12 give two different proofs, one using the factorial formulas and the other combina torial.