Let's begin by putting together some equations:
Seth has charges $39 and then $13 per hour. Since "hour" is our variable, let's write that as $13h where h = the number of hours.
Seth = 39 + 13h, $39 plus $13 times the number of hours
Malcolm charges $55 and then $11 per hour. So:
Malcolm = 55 + 11h, $55 plus $11 times the number of hours
Our goal is to find out how many hours both have to work before they charge the same amount. So let's set our Seth and Malcolm equations equal to one another.
39 + 13h = 55 + 11h, because we want to solve for h to see the number of hours.
First let's subtract 39 from each side:
(39 + 13h) - 39 = (55 + 11h) - 39
13h = 16 + 11h
Now let's subtract 11h from each side:
(13h) - 11h = (16 + 11h) - 11h
2h = 16
Simplify and solve for h by dividing each side by two:
(2h)/2 = (16)/2
h = 8
So Malcolm and Seth would have to work for 8 hours before both earn the same amount. After 8 hours, Seth would earn more than Malcolm. Before 8 hours, Malcolm would earn more than Seth.
Answer:
sigma should be used
Step-by-step explanation:
Given that The mean length of time in jail from the survey was four years with a standard deviation of 1.9 years.
The above given is for sample of 27 size.
For hypothesis test to compare mean of sample with population we can use either population std dev or sample std dev.
But once population std deviation is given, we use only that as that would be more reliable.
So here we can use population std deviation 1.4 only.
If population std deviation is used we can use normality and do Z test
VW = VC + CW
61 = z + 13 + z + 8 = 2z + 21
2z = 61 - 21 = 40
z = 40/2 = 20
z = 20.
If you mean -10.0 - (-2.3) then the answer is -7.7
