Raphael went to the store and bought 2 1/2 pounds of chicken for $9.00. What was the cost per pound of the chicken? Round your a
1 answer:
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Answer:
a) There is a 10.75% probability of observing less than 60 hits in an hour.
b) The 99th percentile of the distribution of the number of hits is 95.21 hits.
c) There is a 24% probability of observing between 80 and 90 hits an hour
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by
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. The sum of the probabilities is decimal 1. So 1-pvalue is the probability that the value of the measure is larger than X.
In this problem, we have that
The web logs of a certain website show that the average number of hits in an hour is 75 with a standard deviation equal to 8.6, so .
a) What’s the probability of observing less than 60 hits in an hour? Use the normal approximation
This is the pvalue of Z when X = 60. So
has a pvalue of 0.1075. This means that there is a 10.75% probability of observing less than 60 hits in an hour.
b) What’s the 99th percentile of the distribution of the number of hits?
What is the value of X when Z has a pvalue of 0.99.
Z = 2.35 has a pvalue of 0.99
So
The 99th percentile of the distribution of the number of hits is 95.21 hits.
c) What’s the probability of observing between 80 and 90 hits an hour?
This is the pvalue of the zscore of X = 90 subtracted by the pvalue of the zscore of X = 80.
For X = 90
has a pvalue of 0.95907
For X = 80
has a pvalue of 0.71904
So
There is a 0.95907 - 0.71904 = 0.24003 = 24% probability of observing between 80 and 90 hits an hour
Check the procedures in the picture attached.
1. Since we are using direct substitution, the only thing we need to do is replace
by 
(the quantity is approaching to) in our quantity to get:
We can conclude that the correct answer is B) -6
2. Again, since we are using direct substitution, th only thing we need to do is replace by 
(the quantity x is approaching to) to get:
We can conclude that the correct answer is D) 31
3. Direct substitution again, so we are going to replace in our quantity by 
to get:
And since cosine of is 0, and any quantity multiplied by zero is zero:
We can conclude that the correct answer is A) 0
4. Here we need to so some algebra first. Notice that if we use direct substitution, the denominator will be zero, and we cannot divide by zero. So lets massage our quantity first:
Now, we can use direct substitution to get:
We can conclude that the correct answer is B) 4
1. Since we are using direct substitution, the only thing we need to do is replace
We can conclude that the correct answer is B) -6
2. Again, since we are using direct substitution, th only thing we need to do is replace
We can conclude that the correct answer is D) 31
3. Direct substitution again, so we are going to replace
And since cosine of
We can conclude that the correct answer is A) 0
4. Here we need to so some algebra first. Notice that if we use direct substitution, the denominator will be zero, and we cannot divide by zero. So lets massage our quantity first:
Now, we can use direct substitution to get:
We can conclude that the correct answer is B) 4