Answer:
The mean is 80 and the standard deviation is 20. Therefore we have
65 is 0.75 standard deviation below the mean.
Step-by-step explanation:
z = 
Since 85 is 0.25 standard deviations above the mean we have
or 0.25·σ = 85 - μ......1
1.5 = 
or 1.5·σ = μ - 50..............2
From 1 we have σ = 340 - 4·μ substituting into 2 gives
1.5·(340 - 4·μ) = μ - 50 ⇒ 510 - 6·μ = μ - 50
7·μ = 560 or μ = 80
Therefore σ = 340 - 4·μ = 340 - 4·80 = 20
A value, x, 0.75 standard deviation below the mean is given by
0.75 = 
which gives 15 = 80 - x or
x = 65.
Answer:
9/32 or 0.28125
Step-by-step explanation:
8 parents and 4 teachers
There are 12 possible outcomes.
probability = # of favorable outcomes / # of possible outcomes
Let's do the teachers first.
There are 4 teachers, and we are finding the probability for 3 of them being picked.
Therefore,
P = 3/4
Now let's do the parents.
There are 8 parents, and we want 3.
Therefore,
P = 3/8
Now, we do 
Therefore, the chance of 3 teachers and 3 parents being picked out of 4 teachers and 8 parents is 9/32, or in decimal form 0.28125.
Hope this helped!
ANSWER:
We'll first find the increase in CO2 level, between 1959 and 2005.
Now, Percent of increase.
<u>Increase carbon-dioxide levels</u>:— 50.
<u>Percent increase</u>:— 13.62%
Answer:
300 In
Step-by-step explanation:
1 foot = 12in
so, 25×12 =300
Answer:
I think it's 5 triangle are needed to make star
