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1 answer:
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Answer:
a)
b)
c)
Step-by-step explanation:
1) 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".
Let X the random variable that represent interest on this case, and for this case we know the distribution for X is given by:
And let represent the sample mean, the distribution for the sample mean is given by:
On this case
Part a
We want this probability:
The best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
Part b
We want this probability:
If we apply the formula for the z score to our probability we got this:
Part c
We are interested on this probability
If we apply the Z score formula to our probability we got this:
And we can find this probability on this way:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
Answer:
Step-by-step explanation:
slope (rise over run) choose 2 points that are easy to figure out. Count up and over to get the slope
(0,3) and (4,4)
3 to 4 is 1
0 to 4 is 4
slope is 1/4
y intercept is b- so +3
y=
Answer: They should order 160 steak, 80 lobster and 260 chicken. The total cost for the meals would be $4460
Step-by-step explanation:
The cruiser will have 400 passangers on board. By taking into account that the cruise line decided to buy 25% more of meals than bookings, we can conclude that in order to calculate the ammount of meals they will order, we have to take the number of passangers on board, 400, and add to it 25% more. So the number of meal orders will be 400 + (1/4 * 400) = 500.
Let's use the letter S to simbolize the ammount of steak they should buy, with L the ammount of lobster, and with C the ammount of chicken. The sum of those ammounts should be 500, so we deduce this formula
we can replace C with 500 - S - L. Since at least forty percent of the passangers will have steak dinner and at least twenty percent will have lobster, we obtain this relations:
We note the total cost of the meals (in $). The value of
will depend on the values of S and L. Using the information we are given about the cost of each dinner, and recalling that C was 500- S - L, we can represent
by this formula
Which is equal to
We want to minimaze the value of , since 3*S + 6*L will get bigger as we use bigger values of S and L, then we will be in a good position if we take the values of S and L as low as possible.
With the restriction we obtained, the lowest values of S and L we can take are 160 and 80 respectively; so we take those values. In conclusion
- S = 160 (number of steak)
- L = 80 (number of lobster)
- C = 500-160-80 = 260 (number of chicken)
The total cost of the meals is