The phases of the moon are periodic and repetitive. A new moon occurs when no moon is visible to an observer on Earth. During the first quarter, half of the side of the moon facing the Earth is visible. During a full moon the entire side of the moon is visible. During the last quarter the other half of the side of the moon facing Earth is visible. The U. S. Naval Observatory lists the following dates for phases of the Moon in the year 2008.

Date
Moon Phase
x: Days since Jan. 8
y: The Amount of Moon Visible
Jan 8
New
0
0
Jan 15
1st quarter
7
0.5
Jan 22
Full
13
1
Jan 30
Last quarter
22
0.5
Feb 7
New
30
0
Feb 14
1st quarter
37
0.5
Feb 21
Full
44
1
Feb 29
Last quarter
52
0.5
Mar 7
New
59
0
Mar 14
1st quarter
66
0.5

Using the information above, plot the data points and produce a sine regression model for the data. Round a, b, c, and d to the nearest 0.001. Then use your model to predict how much of the moon will be visible 1 full year later, provided the sky is clear and assuming the year has 365 days. Give your answer as a percent.
a.
11% of the moon will be visible
b.
42% of the moon will be visible
c.
0% of the moon will be visible
d.
73% of the moon will be visible

irst, find the z score of a score of 80. this is given by the formula z = (x-u)/o, where x is the score, u is the mean, and o is the standard deviation. this gives

z = (80-78)/12 = 1/6 = .1667

now, find what percentile a z score of 1/6 correlates to in the normal distribution.

a z score of 1/6 = .1667 is equivalent to the 56.36th percentile of the distribution. so the probability a score is over this is 1-.5636 = .4364

the mean of a sample mean is equal to the original mean. however, the standard deviation of a sample mean is equal to the original standard deviation divided by the square root of n (sample size). so the new standard deviation is 12/sqrt(16) = 3.

the new z score is 80-78/3 = 2/3 = .667. this is equivalent to the 74.86th percentile. so the probability that the mean will be greater than this score is 1-.7486 = .2514.

a) at most means it can cost $12 or less

so the inequality sign would be ≤

you would then need to multiply the number of toppings by the 0.35 for each one and add it to the cost of the cheese pizza.

the equation would be 9.99 + 0.35x ≤ 12

b) using the above equation:

9.99 + 0.35x ≤ 12

subtract 9.99 from each side:

0.35x ≤2.01

divide both sides by 0.35:

x ≤ 2.01 / 0.35

x ≤5.74

at most you could have 5 toppings.

the 5 topping pizza would cost: 0.35 x 5 = 1.75 + 9.99 = $11.74

answer: the answer is 100 x 12,500, which is 1,250,000.

step-by-step explanation: emily solved for a part when she should have solved for the whole.  

875,000 should be the numerator of the equivalent ratio.  

70 x 12,500 is 875,000.