Answer:
A sample size of 385 is needed.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
That is z with a pvalue of 
, so Z = 1.96.
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
You feel that a reasonable estimate of the standard deviation is 10.0 hours.
This means that 
What sample size is needed so that the expected margin of error of your estimate is not larger than one hour for 95% confidence?
A sample size of n is needed. n is found when M = 1. So
Rounding up:
A sample size of 385 is needed.
Answer:
x = 5.6 or you can write like this: x = 5 3/5
Step-by-step explanation:
Team A: 15 points
Team B: 3 points
Team A has twelve more points than Team B:
A = B + 12
Team A has five times as many points as Team B:
A = B × 5
A = 5B
substitute "A" with "B + 12" to solve for B:
A = 5B
(B + 12) = 5B
B + 12 = 5B
12 = 5B - B
12 = 4B
3 = B
Team B has 3 points
now substitute "B" with 3 to solve for A:
A = 5B
A = 5(3)
A = 15
Team A has 15 points
Check your answer by inputting both values into either equation:
A = 5B
(15) = 5(3)
15 = 15 ✔
A = B + 12
(15) = (3) + 12
15 = 15 ✔
