Answer:
The minimum sample size required to ensure that the estimate has an error of at most 0.14 at the 95% level of confidence is n=567.
Step-by-step explanation:
We have to calculate the minimum sample size n needed to have a margin of error below 0.14.
The critical value of z for a 95% confidence interval is z=1.96.
To do that, we use the margin of error formula in function of n:

The minimum sample size to have this margin of error is n = 567.
She needs to earn at least 84 to buy the mp3 player
earnings=earningsperhour times numberofhoursworked
earnings per hour=12 dollars
number of hoursworked=h
therefor
earnings=12 ties h or12h
earnings is at least 84
earnings is greater than or equal to 84
earnings<u>></u>84
12h<u>></u>84
solve
12h<u>></u>84
divide both sides by 12
h<u>></u>7
she needs to work at least 7 hours
to graph, draw a line at x=0 and shade to the right, make the line solid
y = 3x - 1
x - y = -9
Subs y in second equation.
x - (3x - 1) = -9
x - 3x + 1 = -9
-2x = -9 - 1
-2x = -10
x = -10/-2
x = 5
Subs x
y = 3x - 1
y = 3.5 - 1
y = 15 - 1
y = 14
58÷40×100 which will give you 145 as the answer.