The american veterinary association claims that the annual cost of medical care for dogs averages $100, with a standard deviation of $30, and for cats averages $120, with a standard deviation of $35.

a) what's the expected difference in the cost of medical care for dogs and cats?
b) what's the standard deviation of that difference?
c) if the costs can be described by normal models, what's the probability that medical expenses are higher for someone's dog than for her cat?
d) what concerns do you have?

a)20$

b)46,1$

c)0,3336

d)No concerns

Step-by-step explanation:

A) To find expected difference of cost of medical care for dogs and cats we can simply subtract average costs of cats and dogs.

Expected difference will be 20$.

B) To find the standard deviation of that difference, we need to square deviations and add them and square root it again.

Expected difference will be 46,1$.

C)We need to find the Z value to find the probability of more expensive dogs than cats in a Vet vise.

Z value of the function is -0,434

From the Z table that you can find at the attachment. The probability is %33,36 or 0,3336

D) This is a subjective part. I don't have any concerns

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40