A quality control manager takes an SRS of 500 phone batteries from factory A, where 5% of the batteries have a defect. the manager also takes an independent SRS of 250 batteries from factory B, where 9% of proportions of the batteries have a defect. The manager will then look at the difference (B-A) between the proportions of defective batteries in each sample. What are the mean and standard deviation of the sampling distribution of the difference in sample proportions?

*answer choices attatched*

If possible an explanation would also be appreciated; any unrelated answer is getting deleted

1- is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis. 2- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis. 3- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in part b?

Lin is writing an equation to model the proportional relationship between y, the total cost in dollars of downloading videos from a website, and x, the number of videos downloaded. she knows that the total cost to download 3 videos was $12. her work to find the equation is shown below. joylin’s work step 1 k= 3/12= 0.25 step 2 y= 0.25x where did joylin make her first error?

With number 11 ( show how you got the answer)