Answer:
What we know is that 30% of the group have brown hair and are girls. It means that in the other 70% we have the boys with brown hair, the other boys and the other girls.
In the case all the girls have brown hair, the 70% remaining would be boys. So 70% of then would have brown hair. (0.7*0.7=0.49 -> 49% of the children would be brown hair) so 49% (boys) and 30% (girls) are more than 50%..
Now, let's suppouse that 90% of the group are girls. It means 10% are boys and 70% of that 10% (=7%) are the boys in the group that have brown hair. Now 7% + 30% of the children have brown hair, wich isn't more than the half.
We have explained with two extreme cases that the information is not enough for making a precise answer
Answer:
What's confusing ??? You literally just put a dot on the number line
Example:
1.3, move 3 units to the right of 1 and place a dot there
I'll go out on a limb and suppose you're given the matrix

and you're asked to find the determinant of

, where

and given that

.
There are two properties of the determinant that come into play here:
(1) Whenever a single row/column is scaled by a constant

, then the determinant of the matrix is scaled by that same constant;
(2) Adding/subtracting rows does not change the value of the determinant.
Taken together, we have that
Answer:
The sample size is 4
Step-by-step explanation:
Null hypothesis: The mean is 2
Alternate hypothesis: The mean is less than 2
Mean = 3
sd = sqrt(variance) = sqrt(4) = 2
At 95% confidence level, t-value is 1.960
Assuming the lower bound of the mean is 1.04
Lower bound = mean - (t×sd/√n)
1.04 = 3 - (1.96×2/√n)
3.92/√n = 3 - 1.04
3.92/√n = 1.96
√n = 3.92/1.96
√n = 2
n = 2^2
n = 4