Questions on The Central Limit Theorem. Standard error. Distribution of sample means answered by real tutors!

Tutors Answer Your Questions about Central-limit-theorem (FREE)

Question 1165554: lim (x-> -inf) (x^2+4^-x)/(x^2-4^x)
Click here to see answer by ikleyn(52781)

Question 1178703: Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.
Of 82 adults selected randomly from one town, 66 have health insurance. Find a 90% confidence interval for the true proportion of all adults in the town who have health insurance.
Click here to see answer by CPhill(1959)

Question 1190594: A population consists of (3,8,10,15). Consider all possible sample size 2 that can be drawn with replacement.
-what is the standard deviation of the sampling distribution of means? =
-what is the population mean? =
-what is the population standard deviation? =
-what is the population variance? =
-what is the variance of the sampling distribution of means? =
-what is the mean of the sampling distribution of means? =

A population consists of (3,8,10,15). Consider all possible sample size
2 that can be drawn without replacement.
-what is the variance of the sampling distribution of means? =
-what is the standard deviation of the sampling distribution of means? =
-what is the mean of the sampling distribution of means? =

Click here to see answer by CPhill(1959)

Question 1205257: 1. An investigator decided to construct a frequency distribution with five classes. The following
information was available. For fifty observations made on a characteristic under study, the
first two and the last two frequencies were 6,10,10 and 6 respectively. Given the last class
mark is 66 and upper class limit of the fifth class is 72.
a. Calculate mean, Median and mode.
Click here to see answer by CPhill(1959)

Question 1204215: If limt(e^(ln(ax)) × tan(2a/x))= 8 ' find value of a ?
Click here to see answer by ikleyn(52781)

Question 1204215: If limt(e^(ln(ax)) × tan(2a/x))= 8 ' find value of a ?
Click here to see answer by MathLover1(20849)

Question 1201121: The mean I.Q of a sample of 1600 children was 99. Is it likely that this was a random sample from a population with mean I.Q 100 and standard deviation 12? (Test at 5% level of significance)
Click here to see answer by math_tutor2020(3817)

Question 1200670: lim f(x)
x-1
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Question 1200671: lim f(x)=2x^2-2x^2+3x-3
x-1
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Question 1200672: lim f(x)=2x^2-2x^2+3x-3/x-1
x->1
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Question 1200673: lim g(x)=x^2-4/x+2
x->2
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Question 1200674: slope of the tangent line to the curve g(x)=x^2-4/x+2

Click here to see answer by ikleyn(52781)

Question 1200399: 1. Each child born to a particular set of parents has a probability of 0.25 of having
blood type O. If these parents have 5 children. What is the probability that?
a. Exactly three of them have blood type O.
b. At most 2 have blood type O
c. At least 4 have no blood type O
d. The fifth child have blood type O
e. Compute the mean and variance of this probability distribution
f. Draw the probability distribution table

Click here to see answer by Solver92311(821)

Question 1199283: The area of a rectangle is 46 square inches. If the length is 4 times the width, then find
the dimensions of the rectangle. Round off your answers to the nearest hundredth.

Click here to see answer by josgarithmetic(39617)

Question 1195851: Historically, 93% of the deliveries of an overnight mail service arrive before 10:30 the following morning. If a random sample of 500 deliveries is selected, what is the probability the sample will have more than 95% of the deliveries arriving before 10:30 the following morning?
Click here to see answer by ikleyn(52781)

Question 1190595: SAMPLING DISTRIBUTION WITH AND WITHOUT REPLACEMENT
A population consists of (3,8,10,15). Consider all possible sample size 2 that can be drawn with replacement.
-what is the standard deviation of the sampling distribution of means? =
-what is the population mean? =
-what is the population standard deviation? =
-what is the population variance? =
-what is the variance of the sampling distribution of means? =
-what is the mean of the sampling distribution of means? =

A population consists of (3,8,10,15). Consider all possible sample size
2 that can be drawn without replacement.
-what is the variance of the sampling distribution of means? =
-what is the standard deviation of the sampling distribution of means? =
-what is the mean of the sampling distribution of means? =

Click here to see answer by MathLover1(20849)

Question 1186868: The mean height of an adult giraffe is 17 feet. Suppose that the distribution is normally distributed with standard deviation 0.9 feet. Let X be the height of a randomly selected adult giraffe. Round all answers to 4 decimal places where possible.

c. What is the Z-score for a giraffe that is 18.5 foot tall?

d. What is the probability that a randomly selected giraffe will be shorter than 17.5 feet tall?

e. What is the probability that a randomly selected giraffe will be between 16.7 and 17.2 feet tall?

f. The 70th percentile for the height of giraffes is
ft.
Click here to see answer by ikleyn(52781)

Question 1184696: Let Y1, Y2, Y3, and Y4 be independent, identically distributed variables from a population with mean μ and variance σ(squared). let ȳ = 1/4(y1,y2,y3,y4) denote the average of these random variables. What are the expected value and variance in terms of μ and σ(squared)?
Click here to see answer by robertb(5830)

Question 1178691: An advertising firm states that 27% of households will buy something on the Internet next year. How large a sample is needed to be 92% confident that this proportion is within 5% of true proportion.
Click here to see answer by robertb(5830)

Question 1179918: A recent survey indicated that the average amount spent for breakfast by business managers was $7.58 with a standard deviation of $0.42. It was felt that breakfasts on the West Coast were higher than $7.58. A sample of 81 business managers on the West Coast had an average breakfast cost of $7.65. Find the P-value for the test.
Click here to see answer by Theo(13342)

Question 1178701: Annual precipitation in a certain city is normally distributed with a mean of 99 inches, and a standard deviation of 18 in. Find the probability that the mean annual precipitation during 35 randomly picked years will be less than 101.8 in.?
Click here to see answer by ikleyn(52781)

Question 1178568: A random sample of 75 printers discovered that 25 of them were being used in small businesses . Find the 99% limit for the population proportion of printers that are used in small businesses.
Click here to see answer by JimmyJW(2)

Question 1178567: A sample of size n=11 has a sample mean xbar=15.6 and sample standard deviation s=2.4. Construct a 95% confidence interval for the population mean μ.

Click here to see answer by ewatrrr(24785)

Question 1178440: Of the members of a Boy Scout troop, 15% have received the first aid merit badge. If 40 boy scouts are selected at random, find the probability that four or more will have the first aid merit badge?

Click here to see answer by ikleyn(52781)

Question 1176929: 1,3,5 are the first three terms of a quadratic sequence the 7th term is 35 determine the 6th and 5th term of the sequence detrrmine the nth term
Click here to see answer by greenestamps(13200)

Question 1173381: Question :
The mean for the number of weeks 15 New York Times hard-cover fiction books spent on the bestseller list is 22 weeks. The standard deviation is 6.17 weeks. The mean for the number of weeks 15 New York Times hard-cover nonfiction books spent on the list is 28 weeks. The standard deviation is 13.2 weeks. At α=0.10, can we conclude that there is a difference in the mean times for the number of weeks the books were on the bestseller lists?
PLEASE REQUIRED DETAILED ANSWER:
Click here to see answer by Boreal(15235)

Question 1173382: Question :
The mean life time of a sample of 90 light bulbs produced by a company is computed to be 1570 hours with a standard deviation of 120 hours. If µ is the mean of all bulbs produced by the company, test the hypothesis that µ is equal to 1600 hours against the alternative µ˂ 1600 hours.
Click here to see answer by Boreal(15235)

Question 1163435: the area of a rectangle is 20 square inches. If the length is 4 inches less than 6 times the width, then find the dimensions of the rectangle. Round off your answer to the nearest hundredth.
Click here to see answer by greenestamps(13200)

Question 1161820: A trader sells at #30 each or #150 for six. How much do you save by buying three dozen eggs in sixes instead of separately?
Click here to see answer by ikleyn(52781)

Question 1159202:
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Question 1158683: The maintenance department at the main campus of a large state university receives daily requests to replace fluorecent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 49 and a standard deviation of 9. Using the 68-95-99.7 rule, what is the approximate percentage of lightbulb replacement requests numbering between 49 and 58?

Click here to see answer by Boreal(15235)

Question 1158684: A class is given an exam. The distribution of the scores is normal. The mean score is 80 and the standard deviation is 11. What is the probability that a student scored less than 78?
P(x < 78) =
Express the probability as a decimal rounded to 4 decimal places.
Click here to see answer by Boreal(15235)

Question 1153704: Suppose certain coins have weights that are normally distributed with a mean of 5.661 g and a standard deviation of 0.057 g. A vending machine is configured to accept those coins with weights between 5.551 g and 5.771 g.
According to the certain limit theorem, the distribution of sample means x will have a mean given by u_x=u and a standard deviation given by o_x=o/sqrt n.
What is the mean of the distribution of sample means x? u_x=?
Click here to see answer by Boreal(15235)

Question 1153125: It takes 45 minutes to fill a circular pool with a depth of 18 inches. At this rate how long will it take to fill 35 inches.
Click here to see answer by Alan3354(69443)

Question 1145363: Adult male height is normally distributed with a mean of 68.8 inches and a standard deviation of 2.31 inches. What adult male height separates the lower 64% from the upper 36%? Round your final answer to one decimal places.
Click here to see answer by VFBundy(438)

Question 1145360: A manufacturer knows that their items have a normally distributed lifespan, with a mean of 9.9 years, and standard deviation of 3.1 years.
The 4% of items with the shortest lifespan will last less than how many years?
Click here to see answer by VFBundy(438)

Question 1145101: The human adult male height population has a mean M= 70 and a standard deviation of of 4 (measures given in inches), for human adult females M= 65 and standard deviation of 3.5, also in inches.
Click here to see answer by richwmiller(17219)

Question 1145103: The human adult male height population has a mean M= 70 and a standard deviation of of 4 (measures given in inches), for human adult females M= 65 and standard deviation of 3.5, also in inches.
Click here to see answer by richwmiller(17219)

Question 1145104: The human adult male height population has a mean M= 70 and a standard deviation of 4 (measures given in inches), for human adult females M= 65 and standard deviation of 3.5, also in inches.
Click here to see answer by richwmiller(17219)

Question 1143157: A manufacturer knows that their items have a normally distributed lifespan, with a mean of 8.5 years, and standard deviation of 1.2 years.
If you randomly purchase 16 items, what is the probability that their mean life will be longer than 8 years?
Click here to see answer by rothauserc(4718)

Question 1139135: Preston received a paycheck for $900.00 and he wants to invest it in a savings account. A savings account at bank A earns 4% interest compounded monthly and a savings account at bank B earns 5% simple interest. If Preston plans to deposit the $900.00 and leave it in the account for 3 years, at which bank would he earn more interest?
Click here to see answer by josmiceli(19441)

Question 1131223: The average annual cost of the first year of owning and caring for a large dog is $1843 (US News and World Report, September 9, 2013). The Irish Red and White Setter Association of America has requested a study to estimate the annual first-year cost for owners of this breed. A sample of 50 will be used. Based on past studies, the population standard deviation is assumed known with σ = $255.
a) What is the margin of error for a 95% confidence interval of the mean cost of the first year of owning and caring for this breed?
b) The DATAfile Setters contains data collected from fifty owners of Irish Setters on the cost of the first year of owning and caring for their dogs. Use these data sets to compute the sample mean. Using this sample, what is the 95% confidence interval for the mean cost of the first year of owning and caring for an Irish Red and White Setter?

Click here to see answer by Boreal(15235)

Question 1128748: A raffle has a grand prize of a Caribbean cruise valued at $14,000 with for each ticketa second prize of a Las Vegas getaway valued at $800. If each ticket costs $5 and 8800 tickets are sold, what are the expected winnings far a ticket buyer? Round to the nearest penny.
Click here to see answer by greenestamps(13200)

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