Answer:
a)
b) 
c) Since the p value is higher than the significance level provided we have enogh evidence to FAIL to reject the null hypothesis and we can't conclude that the true means are different at 5% of significance
Step-by-step explanation:
Information given
represent the mean for 1
represent the mean for 2
represent the population standard deviation for 1
represent the population standard deviation for 2
sample size for the group 1
sample size for the group 2
z would represent the statistic
Hypothesis to test
We want to check if the two means for this case are equal or not, the system of hypothesis would be:
H0:
H1:
The statistic would be given by:
(1)
Part a
Replacing we got:

Part b
The p value would be given by this probability:

Part c
Since the p value is higher than the significance level provided we have enogh evidence to FAIL to reject the null hypothesis and we can't conclude that the true means are different at 5% of significance
0.07 x 11.2 = 0.784 -< Answer
Inside a triangle, all inside angles add up to 180°
So, add the two angles:
26.4°+33.7°=60.1°
180°-60.1°=119.9°
b=119.9°
X=6 and Y= 6 square root 2
Step-by-step explanation:
ah, here you go.
come on, now. you know this now ...
again, mutually exclusive attributes in the table (no overlap here) allow us to add the numbers for a total :
4+2+12+10 = 28 students in total.
how many of those 28 fulfill our desired criteria (has a brother) ?
well, it is the sum of the column "has a brother", as it does not matter, if there is also a sister or not.
so, it is 4 + 12 = 16
therefore, the probability to pick a student randomly, who has a brother is
16/28 = 4/7 = 0.571428571...