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Question 1170505: A machine fills pop bottles with a standard deviation of 25 mL no matter what the setting is for the mean. At how many mililiters should the mean be set, so that 90% of the bottles will contain at least 500 mL?
Click here to see answer by CPhill(1987)

Question 1199038: Pasien Dirawat di IGD Rumah Sakit Di sebuah rumah sakit, sampel 8 minggu dipilih, dan ditemukan bahwa rata-rata 438 pasien dirawat di IGD setiap minggu. Standar deviasinya adalah 16. Temukan interval kepercayaan 99% dari rata-rata sebenarnya Asumsikan variabel terdistribusi normal.
Click here to see answer by textot(100)

Question 1200376: In a suburban community, 30% of the households use Brand A toothpaste, 27% use Brand B, 25% use Brand C, and 18% use Brand D. In the foul groups of households, the proportions of residents who learned about the brand they use through television advertising are as follows Brand A, 0.10; Brand B, 0.05; Brand C, 0.20; and Brand D, 0.15. In a household selected at random from the community, it is found that residents learned about the toothpaste through television advertising. What is the probability that the brand of toothpaste used in the household is (a) A, (b) B, (c) C, (d)D?

Click here to see answer by GingerAle(43)

Question 1206682: You have a deck with 52 cards. what is the probability of you pulling a 7 of spades?
Click here to see answer by MathLover1(20850)

Question 1205865: Three person are contesting elections from Same consistuency. Mr. X and Mr. Y have same chance of "but Mr. Z has twice the chance winning, but Mr. Z either Mr. X or Mr.Y. What is the probability that;
(i) Mr. Z wins.
(ii) Mr. X does not win.

Click here to see answer by ikleyn(52856)

Question 1205510: A box contains 10 chocolates, of which 4 are dark chocolates and 6 are milk chocolates. If two chocolates are randomly selected without replacement, what is the probability of getting one dark chocolate and one milk chocolate in any order?
Click here to see answer by ikleyn(52856)

Question 1204966: Business Weekly conducted a survey of graduates from 30 top MBA programs. On the basis of the survey, assume the mean annual salary for graduates 10 years after graduation is 169000 dollars. Assume the standard deviation is 36000 dollars. Suppose you take a simple random sample of 91 graduates. Assume the population is normally distributed.

Note: You should carefully round any intermediate values you calculate to 4 decimal places to match wamap's approach and calculations.
Find the probability that a single randomly selected salary exceeds 166000 dollars.
P(X > 166000) = 0.2023
Enter your answer as a number accurate to 4 decimal places.
Find the probability that a sample of size 91 is randomly selected with a mean that exceeds 166000 dollars.
P(x > 166000) =
Enter your answer as a number accurate to 4 decimal places.
I did the first part but can't find P(xbar > 166000) with sample of 91
part but can not figure out the bottom because when I do it I get a number that does not / can not exist for this problem. please help

Click here to see answer by math_tutor2020(3817)

Question 1204513: The diameter of a brand of tennis balls is approximately normally distributed, with a mean of 2.54 inches and a standard deviation of 0.05 inch. A random sample of 10 tennis balls is selected. What is the probability that the sample mean is less than 2.53 inches?
Click here to see answer by Theo(13342)

Question 1203498: A company estimates that 1% of their products will fail after the original warranty period but within 2 years of the purchase, with a replacement cost of $350.
If they want to offer a 2 year extended warranty, what price should they charge so that they'll break even (in other words, so the expected profit will be 0)
$

Click here to see answer by ikleyn(52856)

Question 1202499: The Great Pyramid of King Khufu was built of limestone in
Egypt over a 20-year time period from 2580 bc to 2560 bc.
Its base is a square with side length 230 m and its height
when built was 147 m. (It was the tallest man-made structure
in the world for more than 3800 years.) The density of
the limestone is about 2400 kg/m3
(a) Estimate the total work done in building the pyramid.
(b) If each laborer worked 10 hours a day for 20 years, for
340 days a year, and did 250 J/h of work in lifting the
limestone blocks into place, about how many laborers
were needed to construct the pyramid?
Click here to see answer by ikleyn(52856)

Question 1202367: A box contains 4 white shirts and 3 blue shirts. Two shirts are picked at random from the box, one at a time without replacement. What is the probability that the first chip is white and the second chip is blue?
Click here to see answer by ikleyn(52856)

Question 1201898: A class consisting of 8 men and 7 women we're 2 selected randomly to represent the class in a dabate find the probability that the 2 selected are (I) both men (ii) both woman (iii) of the same Sex (iv) of the different Sex.
Click here to see answer by ikleyn(52856)

Question 1201663: Please solve this equation:
The mean of a normal probability distribution is 300; the standard deviation is 16.
a. About 68% of the observations lie between what two values?
______________

b. About 95% of the observations lie between what two values?
___________________________
c. Practically all of the observations lie between what two values?
_____________________

Click here to see answer by math_tutor2020(3817)

Question 1201071: 123 year 11 students chose the courses they wanted at the school prom dinner. 75 chose a starter, 106 chose a main course and 81 chose a dessert. 67 chose a main course and dessert, 64 chose a starter and a main course while 49 chose a starter and dessert. Everybody ordered at least one course. Find the probability that a student chosen at random chose all three courses
Click here to see answer by ikleyn(52856)

Question 1200896: Fair six sided die is rolled four times was the probability that the sequence of rolls is 6234
Click here to see answer by math_tutor2020(3817)

Question 1197799: A bag of marbles contains 6 blue, 7 red, and 8 orange marbles. What is the probability of picking a red marble and then an orange marble if you do not replace the first marble?
Click here to see answer by Alan3354(69443)

Question 1197033: The elevator at the Matthews Building of the University of New South Wales starts with 10 passengers at the ground and makes stops at each of the 14 floors above. Assuming that it is equally likely that a passenger gets off at any of these 14 floors, what is the probability that at least two of these passengers will get off at the same floor?
Click here to see answer by ikleyn(52856)

Question 1195825: Suppose commute times in a large city are normally distributed and that 62.50% of commuters in this city take more than 20 minutes to commute one-way. If the standard deviation of such commutes is 6.5 minutes, what is the mean commute?
Click here to see answer by Boreal(15235)

Question 1194055: Compute the area under the normal curve with the following data: μ=35 and σ=3, when x is more than 30 but less than 40. Round to two decimal places and do not include the "percent sign". *

Click here to see answer by ikleyn(52856)

Question 1193884: Suppose Z is a standard normal random variable and let Y = aZ +b, where a > 0 and b are constants.
(a) Show that MY (t) = exp {bt +
a
2
t
2
2
}.
(b) Calculate the probability, P(1.2 < Y < 7) if Y ∼ N(3, 4
Click here to see answer by ikleyn(52856)

Question 1193109: P(x<69.1)=
Click here to see answer by ikleyn(52856)

Question 1189095: A soft drink machine is regulated so that it discharges an average of 200 milliliters per cup. If the
amount of drink is normally distributed with a standard deviation equal to 15 millimeters, a) what fraction of the cups will contain more than 240 milliliters?
b) c) what is the probability that a cup contains between 191 and 209 milliliters? how many cups will likely overflow if 230 milliliters cups are used for the next 1000 di
d)
below what value do we get the smallest 25% of the drinks?

Click here to see answer by Boreal(15235)

Question 1188811: a school with 60 teachers is on alert during a nighttime
storm
to inform teachers whether the school will open the next day , the princeipal will call four teachers
each of whom will then call 2 others
and each of these will again call 2 others
so on untill all 60 have been contacted
how many people have to make 2 calls?
Click here to see answer by ikleyn(52856)

Question 1186477: The waiting times between a subway departure schedule and the arrival of a passenger are uniformly distributed between 0 and 5 minutes. Fine the probability that a randomly selected passenger had a waiting time less than 2.75 minutes.
Click here to see answer by Edwin McCravy(20060)

Question 1185582: 2. The medical Rehabilitation Education Foundation reports that the average cost of rehabilitation forstroke victims is $24,672. To see if the average cost of rehab is different at a particular hospital, a researcher selects a random sample of 35 stroke victims at the hospital and find the average cost of their rehab is $25,250. The standard deviation of the population is $3,251. At α= 0.01, can it be concluded that the average cost of stroke rehabilitation at the particular hospital is different from $24,672?a) State thenull and alternativehypotheses.b) Find the critical value from the appropriate table.c) Compute the test value.d) Make the decision to reject or not reject the null hypothesis.
Click here to see answer by Theo(13342)

Question 1184449: please help me with this question, it would be highly appreciated:
3 tiles with the letter X on them and 3 tiles with the letter O on them are placed in a row. The order is chosen at random. What is the probability that no two adjacent tiles have the same letter on them?
Thank you taking time out of your day to help me!

Click here to see answer by robertb(5830)

Question 1183741: For each of the following tobs values, determine the highest level of
significance associated with the decision taken.5
tobs df Decision
(i) 4.000 17 Reject Ha for a two-tailed test
(ii) 1.200 120 Reject Ha for a one-tailed test
(iii) -2.660 16 Reject Ha for both one-tailed
and two-tailed test
(iv) -1.586 60 Reject Ha for a one-tailed test
Click here to see answer by MathLover1(20850)

Question 1183581: From actual road tests with the tires, Hankook Tires estimated that the mean tire mileage is 36,500 miles and that the standard deviation is 5000 miles. Data is normally distributed.
(i) What percentage of the tires can be expected to last more than 40,000 miles?
(ii) Assume that Hankook Tires is considering a guarantee that will provide a discount on replacement tires if the original tires do not provide the guaranteed mileage. What should the guarantee mileage be if the company wants no more than 10% of the tires to be eligible for the discount guarantee?

Click here to see answer by ikleyn(52856)

Question 1182887: The percentage of the adult population in a large city that are women is 45%.
A court is to randomly select a jury of adults from the population of all adults in
this city. Find the probability that none of the 12 randomly selected adults
from this city is a woman.

1. Determine the binomial parameters, n and p, giving values and descriptions.
2. Determine the question being asked, P(x “=, <, <, >, or >” a number), that is, write the
question symbolically as illustrated in lecture videos (and page 2 of this lab 3 packet).
3. Determine the calculator command needed to solve the problem.
(See separate sheet on using calculator to solve binomial problems.)
4. Use the calculator to find the solution to the binomial probability;
round answers to 4 decimal places.
5. Write your answer in a sentence in terms of the application
Click here to see answer by greenestamps(13203)

Question 1181387: Doris is ranked at the first quartile in her senior class of 300 students. What is her rank in the class?
Click here to see answer by Boreal(15235)

Question 1179759: In Statistics and Probability examination, the average grade was 74 and the standard deviation was 7. If 11.9% of the class is given X’s scores, and the grades follow a normal distribution, what is the lowest possible score X and the highest possible score Y?

Click here to see answer by ewatrrr(24785)

Question 1179519: A man gets a raise of 12% in salary at end of first year and further raises of 16% ,19% and 25% at the end of second, third and fourth years respectively; the raise in each year being calculated on his salary at the beginning of the year. What is the average annual percentage increase?

Click here to see answer by ikleyn(52856)

Question 1179065: At a local high school, GPA's are normally distributed with a mean of 2.9 and standard deviation of 0.6. What is the GPA of the highest 2.5% of the students?
Click here to see answer by ewatrrr(24785)

Question 1178343: The weights of a certain group of high school boys have a normal distribution with a mean of 146 lb and a standard deviation of 10lb. Find the percent of the group having a weight
(a) greater than 154 lb.
(b) less than 132 lb.
Click here to see answer by Boreal(15235)

Question 1177853: If a golfer tees off 50 times on 10,000 square foot course how many times (what is the probability) that he will land on the 1,200 foot green that lies within that 10,000 foot course. :a probability & area question
Click here to see answer by ikleyn(52856)

Question 1177087: In a survey of 250 Voters prior to the election, 16% indicated that they would vote for the ABC candidate. Estimate with 90% confidence the population proportion of voters who support the ABC.
Click here to see answer by Boreal(15235)

Question 1174777: Among 200 patients at a Tikur Anbessa hospital.
Click here to see answer by ikleyn(52856)

Question 1174512: In a certain communications system, there is an average of 1 transmission error per 10 seconds Let the distribution of transmission errors, say X be a Poisson distribution. What is the probe ability of more than 1 error in a communication half minute in duration?
Click here to see answer by Boreal(15235)

Question 1173518: Find the z-score that corresponds to the following areas.
Area to the left is 1.24

Click here to see answer by Theo(13342)

Question 1172896: A phone company keeps statistics on the number of messages text that your customers send each month. According to statistics, the number of messages sent per customer in a month has a normal distribution. The data is shown below.
• The average is 278 messages per month.
• The standard deviation is 19 messages per month.
What is the probability that a customer sends LESS than 316 messages in a month?
Click here to see answer by Boreal(15235)

Question 1172478: The heights of applicants to the police force are normally distributed with mean 170 cm and standard deviation 3.8 cm. If 30% applicants are rejected on account of their low height. What is the minimum acceptable height for the police force?
Click here to see answer by Boreal(15235)

Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270