1.(1) The claim by a weight loss Company is that on average, the client will lose 10 pounds over
first 2 weeks. 50 people who joined the programme are sampled, their weight loss is 9 pounds with a standard deviation of 2.8 pounds. Can we conclude at the .05 level that a person joining the programme will lose less than 10 pounds?
(2) The following is a random sample of 90-day futures prices in dollars for 1 troy oz. of silver from The Wall Street Journal issues in May and June of 1997: 4.74, 4.77, 4.87, 4.91, 4.83, 4.72, 4.92, 4.86, 4.97, 4.71, 4.90, 4.93, 4.75, 4.88, 4.79, 4.83, 4.89.
a. Calculate the mean
c. Standard deviation of the 90-day future price of silver data
(3) A mining company needs to estimate the average amount of copper ore per ton mined. A random sample of 50 tons gives a sample mean of 146,75 pounds. The population standard deviation is assumed to be 35.2 pounds.
a. Give a 95% confidence interval for the average amount of copper in the population of tons mined.
b. Give a 90% confidence interval for the average amount of coper per ton
c. Give a 99% confidence interval for the average amount of coper per ton
(4) An e-commerce Website gets 2,385 visitors on a particular day. Among these, 1790 visitors explore the products by looking at more pages at the site. Among these 1790 visitors who explore the products, 387 make a purchase.
a. If a visitor chosen at random from all those who visited the site, what is the probability that the visitor explored the products
b. If a visitor is chosen at random from all those who visited the site, what is the probability that the visitor made a purchase.
c. If a visitor is chosen at random from all those who explored the products, what is the probability that the visitor made a purchase.
d. Which of the preceding three probabilities is relevant to the design of the home page that leads to product page.
4.(a) A 20.0 L container at 303 K holds a mixture of two gases with a total pressure of 5.00
here are 2.00 mol of Gas A in the mixture, how many moles of Gas B are present? (R = 0.0821 L • atm/(K • mol))
(b) The gas in a 250. mL piston experiences a change in pressure from 1.00 atm to 2.80 atm. What is the new volume (in mL) assuming the moles of gas and temperature are held constant?
(c) Small quantities of Oxygen can be produced by the decomposition of mercury(II) oxide as shown below. Typically, the oxygen gas is bubbled through water for collection and becomes saturated with water vapor. Atomic weight of HgO = 216.6 amu, Atomic weight of Oxygen = 32.00 amu)
2 HgO(s) → 2 Hg(ℓ) + O₂(g)
(i) Assuming that 3.05 grams of HgO was used in this reaction, determine the number of moles of oxygen gas formed.(According to the above chemical equation)
(ii) Assuming 310. 0 mL of Oxygen gas was collected at at 29°C, calculate the pressure of the Oxygen gas that was collected. (R = 0.0821 L • atm/(K • mol)
(iii) If the vapor pressure of water at this temperature equals to 0.042 atm, calculate the pressure reading of this experiment.
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1. Which best describes the difference between single cell and multicellular organisms? *
a. Single-cell organisms can perform all processes in one cell, but multicellular organisms need many cells to do specialized functions together.
b. Single-cell organisms need one cell to function, but multicellular organisms need lots of cells who all have the same job.
c. Single-cell organisms need many cells to do specialized functions together, but multicellular organisms can perform all processes in one cell.
d. Single-cell organisms need multiple cells with similar structures, but multicellular organisms need only one cell.
2. How does your brain move your arm? *
a. The brain sends a message to your bones to move your arm
b. The brain sends a message to your nerves to move your arm
c. The lungs send a message to your muscles
d. The muscles send a message to your brain
3. Which correctly explains the difference between the respiratory and circulatory system? *
a. The respiratory system includes your lungs and the circulatory system includes your heart
b. The respiratory system takes in oxygen and the circulatory system breaks down food
c. The respiratory system takes in water and carbon dioxide, but the circulatory system does not
d. The respiratory system includes the brain and the circulatory system includes to lungs
4. Which of the following is a learned behavior? *
a. Dimples when you smile
b. Ability to sing
d. Hair color
5. These are all examples of: *
6. Which of these does NOT make a new material? *
a. Burning a wooden log
b. Iron nail rusitng
c. Ice melting
d. Mysterious color change
Explain why: *
This is a required question
7. What would you want to put your drink it to keep it cold? *
Metal (good conductor)
Plastic (bad conductor)
Explain why: *
8. How does the sun play a role in the water cycle? *
a. Heats water and turns it into water vapor gas
b. Cools gas to make water droplets and clouds
c. Creates strong winds
d. Causing it to rain
9. What will happen when a metal chair is left outside in the hot sun? *
a. Increase in weight
b. Decrease in weight
c. Increase in size
d. Decrease in size
10. What would the weight of the lemonade be if the water is 3.0 grams, the ice is 2.5 grams, and the mixture is 0.25 grams? *
a. 5.75 g
b. 5 g
c. 6.25 g
d. 10.1 g
6.I have 5 questions I am stuck on. Please help!
1. Enter the correct answer in the box.
Facundo crochets and sells
chets and sells baby blankets, b. Each blanket requires 3 skeins of yarn, and the total number of skeins Facundo uses, y, varies directly as the number of blankets he crochets, b.
Write an equation that models this relationship.
2. The weight of an object, w, varies inversely as the square of its distance from the center of Earth, d. When an astronaut stands in a training center on the surface of Earth (3,960 miles from the center), she weighs 155 pounds. To the nearest tenth of a pound, what will be the approximate weight of the astronaut when she is standing on a space station, in orbit 240 miles above the training center?
3. The square of g varies inversely as h. When g = 16, h = 2. What is the value of h when g = 40?
4. The number of days, d, it will take Manny to read a book varies inversely as the number of pages, p, he reads per day. If k is the constant of variation, which equation represents this situation?
5. The battery life for Bruhier’s cell phone is longer when he has fewer apps running. When only one app is running, the battery will last for 16 hours. When four apps are running, the battery will only last for 4 hours.
7.Suppose you measure a block’s weight by hanging it from a spring scale. You find that it
weighs 34.0 N
34.0 N when it’s not in the water. When it’s submerged in water (the density of water is
1.00 x 103 kg/m3) the scale now reads 27.0 N. (a) What is the density of the block? (b) If you
suspended another object from the block that has a density of 3.20 x 103 kg/m3, with both objects
submerged, what would the object's mass need to be for the scale to once again read 34.0 N?
Note: Part (a) is worth 7 points, and part (b) is worth 8 points.