Answer:
The 99% confidence interval is between 62.36%(lower bound) and 89.64%(upper bound).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
A sample of 65 students from the freshmen class is used and a mean score of 76% correct is obtained.
This means that 
99% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

0.6236*100 = 62.36%
0.8964*100 = 89.64%
The 99% confidence interval is between 62.36%(lower bound) and 89.64%(upper bound).
Answer:No
Step-by-step explanation:
Given system of equation is:
2x + 3 = y
2x + y = 15
To check whether (2,7) is solution to this system or not, we will put x=2 and y=7 in both equations.
Putting x=2 and y=7 in Eqn 1
2(2) + 3 = 7
4 + 3 = 7
7 = 7
Thus the ordered pair satisfies the equation
Putting x=2 and y=7 in Eqn 2
2(2) + 7 = 15
4 + 7 = 15
11 ≠ 15
The ordered pair do not satisfy the second equation.
Hence,
(2,7) is not a solution to the given system of equations.
Answer:
5 + 5 =10
Step-by-step explanation:
it should have been 4 +6 = 10
X+y=6
x=10
10+y=6
y=-4
10=-4+z
-4+z=10
z=10+4
z=14
So the correct answer is 14