Hope this helps with the answer to your question:) (sorry I didn't know how to do question 30)
Ok...so u have 4 people sharing this plan...they each pay for their own data..however, the $ 90 flat rate is split between them equally.
90/4 = 22.5....so each of them pay 22.50 each for the flat rate.
so John's equation is : 22.5 + 0.25x = 147.50
1. (-2,-5)
2. (-3,8)
3. (-8,-9)
4. (-2,-7)
1. Answer: given: an average of 28 pounds
a.
Find z values corresponding to 27 and 31:
z=%2827-28%29%2F2=-1%2F2=-0.5
z=%2831-28%29%2F2=3%2F2=1.5
Find the area between z+=+-0.5 and z=+1.5
Table E gives us an area of 0.9332-0.30=0.6247=> The probability is 62.47%
b.
Find z values corresponding to 30.2
z=%2830.2-28%29%2F2=2.2%2F2=1.1 Find the area to the right of z+=1.1
it gives you an area of 0.1357=> The probability is 13.57%