Answer:

Step-by-step explanation:
The probability that Boris is assigned a moderate-difficulty question would be the ratio of number of moderately difficult questions to the number of total questions available.
The quiz consists of 2 high difficulty, 7 moderate difficulty, and 6 low difficulty questions. That is 2 + 7 + 6 = 15 questions in total.
and
the number of moderately difficult questions is 7
Hence the probability would be 7/15
Answer:
you have 9 yes and 3 no. so 3/9=1/3=.333
Answer:
a. the less variability it has
Step-by-step explanation:
The standard deviation is a measure of the amount of variation or dispersion of a set of values.
When your standard deviation is big your data is more dispersed.
When your standar deviation is small your mean is a representative index of your data, and there is less variability.
If there was no dispersion of the data (if all your data be the same) then the standard deviation will be 0.