Answer:
Option C is right
Step-by-step explanation:
Given are two samples
I group has sample size 90, mean = 9.2 and std dev =0,.37
II group has sample size 70, mean = 7.3 and std dev = 0.58
we find that mean difference i.e. difference between mean hours of sleep between two groups
= 9.2-7.3 = 1.9
Std error for difference = 0.0620
Since sample size is sufficiently large we can use Z critical for 99%
i.e. 2.58
Margin of error =±2.58(0.062)
=0.16
Hence confidence interval 99% for difference in hours of sleep
= (1.9-0.16,1.9+0.16)
=(1.74, 2.06)
I think it’s the second one
Answer:
See below.
Step-by-step explanation:
Formula: A = πr²
Since the radius is 4, we fill in the formula with the radius.
A = (3.14)4²
A = (3.14)16
A = 50.24
-hope it helps
Given:
The system of equations is
...(i)
...(ii)
To find:
The number that must be multiplied with the second equation to eliminate the y-variable.
Solution:
Coefficient of y variable in equation (i) is 3 and in equation (ii) is -1.
To eliminate y-variable the absolute value of coefficients of y-variables should be same.
So, we need to multiply the second equation by 3 to eliminate the y-variable
Multiplying equation (ii) by 3, we get
...(iii)
Adding (i) and (iii), we get
Divide both sides by 7.
Put x=12 in (i).
Divide both sides by 10.
Therefore, x=12 and y=10.
