Answer:
And if we solve for a we got
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the hourly rates of a population, and for this case we know the distribution for X is given by:
For this part we want to find a value a, such that we satisfy this condition:
(a)
(b)
Both conditions are equivalent on this case. We can use the z score again in order to find the value a.
As we can see on the figure attached the z value that satisfy the condition with 0.80 of the area on the left and 0.20 of the area on the right it's z=0.842. On this case P(Z<0.842)=0.8 and P(z>0.842)=0.20
If we use condition (b) from previous we have this:
But we know which value of z satisfy the previous equation so then we can do this:
And if we solve for a we got
Answer: 56 / 729
Step-by-step explanation: (4 * 2 * 7) / (9^3)
Amount of tax on the book (s) is $0.72
Step-by-step explanation:
- Step 1: Given 6/100 = s/12
- Step 2: Cross multiply to solve for s
⇒ 6 × 12 = 100 × s
⇒ 72 = 100s
⇒ s = 72/100 = 0.72
Answer:
8 sqrt(5)
Step-by-step explanation:
sqrt(45) + sqrt(125)
Rewriting
sqrt(9*5) + sqrt( 25 *5)
we know sqrt(ab) = sqrt(a) sqrt(b)
sqrt(9) sqrt(5) + sqrt(25) sqrt(5)
3 sqrt(5)+5 sqrt(5)
Add like terms
8 sqrt(5)