B is actually the correct answer i just took the test and got it right
[[x]] means to round down to the greatest integer less than or equal to x.
A) Variance = 10.24
B) Standard Deviation = 3.2
One of the measurements of dispersion is the standard deviation, which is exclusively used for quantitative data. It aids in determining if the data's mean is a suitable measurement to reflect the core value.
TIME FREQUENCY(f) MIDPOINT(x) d d² fd fd²
0 - 0.9 43 0.45 -3 9 -129 387
1.0 - 1.9 17 1.45 -2 4 -34 68
2.0 - 2.9 19 2.45 -1 1 -19 19
3.0 - 3.9 18 3.45 0 0 0 0
4.0 - 4.9 14 4.45 1 1 14 14
5.0 -5.9 16 5.45 2 4 32 64
∑f = 127
∑fd = -136
∑fd² = 552

Standard Deviation = 

√4.35 - √1.15
Standard Deviation = 3.2
(SD)² = (3.2)² = 10.24
Variance = 10.24
To know more about standard deviation, refer to this link :
brainly.com/question/12402189
#SPJ1
It should be A= 1/2bh but im not sure why you wrote those extra things. Are we supposed to use them?
Answer:
Step-by-step explanation:
To find median and mode for
a) In a uniform distribution median would be
(a+b)/2 and mode = any value
b) X is N
we know that in a normal bell shaped curve, mean = median = mode
Hence mode = median = 
c) Exponential with parameter lambda
Median = 
Mode =0