Answer:
C. Claire has 10 country CDs and 5 Jazz CDs
Step-by-step explanation:
means that 10 out of 15. So we can assume that in total she has 15 CDs and 10 of them are Country and the other is Jazz.
This would rule out choice D.
If we reduce this fraction then we would have:
This means that two-thirds of her CDs are country music. So this would rule out A and B choices.
Now C is correct because 10 country plus 5 Jazz is equal to 15 CDs. So we have the correct total.
The answer is C.
Answer:
a) 0.1587
b) 0.0475
c) 0.7938
Step-by-step explanation:
Let's start defining our random variable.
X : ''Thickness (in mm) of ancient prehistoric Native American pot shards discovered in a Hopi village''
X is modeled as a normal random variable.
X ~ N(μ,σ)
Where μ is the mean and σ is the standard deviation.
To calculate all the probabilities, we are going to normalize the random variable X.
We are going to call to the standard normal distribution ''Z''.
[(X - μ) / σ] ≅ Z
We normalize by subtracting the mean to X and then dividing by standard deviation.
We can find the values of probabilities for Z in a standard normal distribution table.
We are going to call Φ(A) to the normal standard cumulative distribution evaluated in a value ''A''
a)
Φ(-1) = 0.1587
b)
1 - Φ(1.666) = 1 - 0.9525 = 0.0475
c)
Φ(1.666) - Φ(-1) = 0.9525 - 0.1587 = 0.7938