Answer:
a) Sample mean: 48.71
Sample median: 48.3
Sample variance: 5.41
Sample standard deviation: 2.37
Step-by-step explanation:
a) Sample mean:

Sample median: M=48.3
Note: I order the data increasingly and take the value N / 2 = 40. In this way there are 39 values above and 39 values below the median.
Sample variance:

Sample standard deviation

b)
H = -1/2; h = 2
There are two answers for this question, -1/2 (or -0.5) and 2.
X number of male students
Y number of female students
Z number of the adults
X=(1 + 7)Z=8Z
Y= X/2
X +Y +Z = 82
8Z +8Z/2 +Z=82 implies Z=82/26=3.1
so we take Z= 3
X= 24
and Y = 12
Answer:
Number of years between 1950 and 2100 =

150 = 50 + 50 + 50 years.

So, total population in 2100 is 375,000,000.