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.Hi, i have a task where i need to calculate the 3 months weighted moving average for May 2021, The
eight should be based on the count of sales for the previous period, the actual period and the next period.
In the excel you can see the housing data:
sum of prices(K)
sum of the asses value(T)
K/T value (sum of prices/sum of the asses value)
The answer i'm looking for is that for May 2021 the price development in percentage should be 9.5% compared to three month back. To calculate the price development you just divide the K/T value, for example:
period 1 K/T value = 1.4
period 4 K/T value = 1.9
Price development = (1.9/1.4)-1 = 35.7% increase.
So i want to see 9.5% increase on May 2021 compared to 3 months earlier.
7.(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.