5x + y = -13.....multiply by -3
4x + 3y = -17
-----------------
-15x - 3y = 39 (result of multiplying by -3)
4x + 3y = -17
-----------------add
-11x = 22
x = -22/11
x = -2
5x + y = -13
5(-2) + y = -13
-10 + y = -13
y = -13 + 10
y = -3
solution (-2,-3)
Answer: The 90% confidence interval for the population mean μ is between 82.85 and 85.15,
Step-by-step explanation:
When population standard deviation is not given ,The confidence interval population proportion is given by (
):-
, where n= Sample size.
s= Sample standard deviation
= sample mean
t* = Critical t-value (Two-tailed)
As per given , we have
n= 64
Degree of freedom : df = n-1=63
s= 5.5
Significance level : 
Two-tailed T-value for df = 63 and would be
(By t-distribution table)
i.e. t*= 1.669
The 90% confidence interval for the population mean μ would be
∴ The 90% confidence interval for the population mean μ is between 82.85 and 85.15,
Answer:
Option B, 8/5 hr
Step-by-step explanation:
1/2 + 1/8
1*4 / 2*4 + 1/8
4/8 + 1/8
5/8 = 1/t
5t / 5 = 8 / 5
t = 8/5
Answer: Option B, 8/5 hr
It is not possible to select a single group from the primary school, since being a single group it could not in any way represent the entire primary school.
Choosing a group would provide the average height for that group, not the entire primary.
Assumptions can be made that the course of half of the primary would theoretically give us a more accurate representation, but the objective is to select a number of students from each course and there would be a representative sample of the entire primary.
The answer is 9.
I hope that helps you!
