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
To solve for the variable
, we have to make it alone. The first thing we do is add
to both sides of the equation:

Now add
to both sides:

Finally, divide both sides by 16 to get the final answer:

Therefore,

Hope this helps!
Answer:
8
Step-by-step explanation:
Set up a ratio problem:
25 hours/2 tests = 100 hours/x
25x = 200
x = 8
Answer:
Yes, result is significant ; PVALUE < α
Step-by-step explanation:
Given :
x = 536
n = sample size = 1012
Phat = x / n = 536 / 1012 = 0.5296 = 0.53
H0 : P0 = 0.5
H1 : P0 > 0.5
Test statistic :
(Phat - P0) ÷ sqrt[(P0(1 - P0)) / n]
1-P0 = 1 - 0.5 = 0.5
(0.53 - 0.5) ÷ sqrt[(0.5*0.5)/1012]
0.03 ÷ 0.0157173
= 1.9087
Pvalue :
Using the Pvalue from test statistic :
Pvalue = 0.02815
To test if result is significant :
α = 0.05
0.02815 < 0.05
Pvalue < α ; Hence, result is significant at α=0.05; Hence, we reject H0.
0.8 is 20% of 4. This is because 20% of something occurs when something is divided by 5, since it is 1/5 of 100. You multiply 0.8*5, and you get 4.