Answer:

Step-by-step explanation:
Z-score:
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question:

You listen to the radio station for 1 hour, at a randomly selected time, and carefully observe that the amount of advertising time is equal to 17 minutes. Calculate the z-score for this amount of advertising time.
We have to find Z when X = 17. So



Answer:
a. 
b. 
Step-by-step explanation:
a. 
A mixed fraction of the form 



b. 
A mixed fraction of the form 




Hence, the answer.
To solve this problem you must apply the proccedure shown below:
1. You have that the ellipse given as a vertical major axis (a=13), therefore, taking the ellipse with its center at the origin, you have the following equation:
(y^2/a^2)+(x^2/b^2)=1
2. You have the distance from the center of the ellipse to the focus:
c=12, therefore, you can calculate the value of b, the minor radius:
c^2=a^2-b^2
b=√(13^3-12^2)
b=5
3. Therefore, the equation is:
a^2=169
b^2=25
(y^2/169)+(x^2/25)=1
The answer is: (y^2/169)+(x^2/25)=1
Answer:
1/5
Step-by-step explanation:
There are 3 numbers of less than 4 (1, 2 and 3) and there are 2 multiples of 9 (9 and 18). So there are 5 favourable outcomes and 25 possible outcomes. So you put 5/25 and cancel down, which makes 1/5. I hope this helps!
Answer:
i think if it were me i whould divide 300 dide 15
Step-by-step explanation: