2. Suppose it is claimed that amongst the population of STM1001students, the number of items bought online in the past year is normallydistributed with a mean of μ = 20 and variance of o² = 25. Furthersuppose that we wish to study the mean of the population by taking arandom sample of n = 61 STM1001 students. Using this information,write down the distribution of the sample mean YN3. Following on from the previous question, what is the probability thawhen we take a random sample of n 61 STM1001 students, thesample mean would be greater than 20.3521?5. AWhatknown that

given data normal distributionμ = 20σ2 = 25∴σ = 25 = 5n = 61P(x¯ >20.3521) = ?

Answered: 2. Suppose it is claimed that amongst…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

See similar textbooks

Similar questions

3. Suppose that the student's standard test on a given year had a normal distribution with mean of 800 and variance 100. а. A student is chosen at random. What is the probability that the sample score is grater than 815? b. 400 students are randomly chosen and the mean score, is calculated. What is the probability that is greater than 801.5.
2. A department store receives an average of 5 returned items per day. The probability that a returned item has an available replacement is 0.65. [Hint: there are two separate distributions here.] d. e. f. Calculate the probability that there are 4 returned items and none has available replacements in a certain day. Calculate the variance and the mean of the returned items. Calculate the variance and the mean of the replaced items. 2
2. Suppose it is claimed that amongst the population of STM1001 students, the number of items bought online in the past year is normally distributed with a mean of u 20 and variance of o2 = 25. Further suppose that we wish to study the mean of the population by taking a random sample of n = 61 STM1001 students. Using this information, write down the distribution of the sample mean, X. Note: In each box, enter a single number rounded to four decimal places where relevant. (2 marks) X~ N( 20 0.4098 2 4. Again following on from the previous question, what is the probability that when we take a random sample of n = 61 STM1001 students, the sample mean would be either greater than 20.3521 or less than 19.6479? [int. orty will b own that
One sample has n=7 and SS=35 and a second sample has n =17 and SS =45. What is the pooled variance for these two samples?
4. Researchers working for a sports drink company would like to know if a new blend if its popular sports drink can help improve marathon runners' final running time. Marathon times, Y, are known to follow a Normal distribution. Suppose that runners using the old blend sports drink have a mean finishing time of 300 minutes (µ = 300 minutes). A random sample of 20 runners was selected to use the new blend of sports drink in a marathon, finishing with an average time of 270 minutes and a standard deviation of 20 minutes (y = 270 min, s = 20 min). Can it be claimed that the new blend lowers finishing times? COr is it possible that random chance alone can explain the discrepancy? Carry out a hypothesis test of the true mean u using the 4- step procedure. Set your alpha-level to 0.05. %3D c. Which test statistic and sampling distribution under the null should we use? O i. z-score; standard Normal O ii. t-statistic; Student'st
4. Researchers working for a sports drink company would like to know if a new blend if its popular sports drink can help improve marathon runners' final running time. Marathon times, Y, are known to follow a Normal distribution. Suppose that runners using the old blend sports drink have a mean finishing time of 300 minutes (H = 300 minutes). A random sample of 20 runners was selected to use the new blend of sports drink in a marathon, finishing with an average time of 270 minutes and a standard deviation of 20 minutes (y = 270 min, s = 20 min). Can it be claimed that the new blend lowers finishing times? Or is it possible that random chance alone can explain the discrepancy? Carry out a hypothesis test of the true mean u using the 4- step procedure. Set your alpha-level to 0.05. a. Which is the correct null hypothesis? O i. Ho: µ = 300 min O ii: Ho: µ = 270 min %3D O ii. Ho: µ < 300 min iv: Ho: µ < 270 min
suppose that we have disjoint normal populations A and B and we want to find the standard error estimate for estimating the difference in their means. We have an IRS from A of size 8 with variance 25 and an IRS from B of size 9 with variance 16. What is the resulting standard error estimate if we assume both populations have the same population variance?
2. A department store receives an average of 5 returned items per day. The probability that a returned item has an available replacement is 0.65. [Hint: there are two separate distributions here.] d. e. f. Calculate the probability that there are 4 returned items and none has available replacements in a certain day. Calculate the variance and the mean of the returned items. Calculate the variance and the mean of the replaced items. 2
1. Six batteries taken at random from a large lot were subjected to life tests with the following results: 19, 22, 18, 16, 25, and 20 hours. Find the probability that the sample mean of x= 20 hours, as observed here, or one less than 20 hours could arise if the true mean of the lot of batteries is 21.5 hours, assuming a known variance of o = 10 hours, for the individual batteries in the lot. %3D
Pavan.88.9
27.
The human resources department of a major corporation announced that the number of people interviewed by the corporation in one month has a mean of 101 and a variance, oʻ, of 266. The management of the corporation suspects that the variance exceeds 266. A random sample of 10 months yielded a mean of 105 interviews, with a variance of 378. If we assume that the number of people interviewed by the corporation in one month follows an approximately normal distribution, is there enough evidence to conclude, at the 0.1 level of significance, that the management's claim is correct? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified below. (If necessary, consult a list of formulas.) (a) State the null hypothesis H, and the alternative hypothesis H,. p H. :0 H, :0 (b) Determine the type of test statistic to use. (Choose one) ▼ O=0 OSO (c) Find the value of the test statistic. (Round…

Recommended textbooks for you

A First Course in Probability (10th Edition)

Probability

ISBN:

9780134753119

Author:

Sheldon Ross

Publisher:

PEARSON

A First Course in Probability

Probability

ISBN:

9780321794772

Author:

Sheldon Ross

Publisher:

PEARSON

A First Course in Probability (10th Edition)

Probability

ISBN:

9780134753119

Author:

Sheldon Ross

Publisher:

PEARSON

A First Course in Probability

Probability

ISBN:

9780321794772

Author:

Sheldon Ross

Publisher:

PEARSON

SEE MORE TEXTBOOKS