Problem 4 The scores of individual students on the American College Testing (ACT)
composite college entrance examination have a normal distribution with mean
18.6 and standard deviation 5.9.
4a. What is the probability that a single student randomly is chosen from all those
taking the test, scores 21 or higher? Round your percentage to 2 decimals.
Your answer
4b. What is the probability that the mean score of an SRS of 40 students chosen
from all those taking the test is 21 or higher? Round your percentage to 2
decimals.
Your answer

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

company a

step-by-step explanation:

using the linear regression models , it is found that company a   pays about $14 more. but using the same regression (linear) company b pays about $10 more.

so company a pays more than b

income. 10x+1300

expenses 3x+(1800+1500)

expenses 3x+3300

to break even:

income = expense,

10x + 1300 = 3x + 3300,

solve for x.

step-by-step explanation:

mark brainliest