1. Mathematics

    The standard deviation of given population is 4.5 with a mean of 60 and the refit population has a standard deviation of 5.2 with a mean of 75. Calculate the coefficient of variation for both populations and comment on the results.

    asked by Ray on July 22, 2011
  2. Math

    The mean of a sample of 25 was calculated as xbar = 500. The sample was randomly drawn from a population whose standard deviation is 15. Estimate the population mean with 99% confidence. B.) Repeat part (a) changing the population standard deviation to 30.

    asked by Joe on April 27, 2010
  3. statistics

    How do we compute sample size fluctuations? Suppose we have a population of 16000 and a sample size of 30, and the number of samples 1000, what will be the impact on population mean and standard deviation when the population is normally distributed? When

    asked by Nasir on December 1, 2011
  4. sample size/ standard deviations

    How do we compute sample size fluctuations? Suppose we have a population of 16000 and a sample size of 30, and the number of samples 1000, what will be the impact on population mean and standard deviation when the population is normally distributed? When

    asked by ut on December 1, 2011
  5. Math (Statistic)

    Considered the sampling distribution of a sample mean obtained by random sampling from an infinite population. This population has a distribution that is highly skewed toward the larger values. a) How is the mean of the sampling distribution related to the

    asked by Jennifer on February 19, 2007
  6. Statistics

    In an essay of 250-500 words, thoroughly address the following items and respond to the related questions: 1.Define the term standard deviation. Why is it important to know the standard deviation for a given sample? What do researchers learn about a normal

    asked by Andrew on January 23, 2014
  7. statistic

    1. A distribution has a standard deviation of   12. Find the z-score for each of the following locations in the distribution. a. Above the mean by 3 points. b. Above the mean by 12 points. c. Below the mean by 24 points. d. Below the mean by 18 points.

    asked by Nickie on January 26, 2013
  8. statistics

    what are the mean and standard deviation of a sampling distribution consisting of samples of size 16? these sameples were drawn from a population whose mean is 25 and who standard deviation is 5. a. 25 and 1.25 b. 5 and 5 c. 25 and 5 d. 5 and 1.25 e. 25

    asked by helga on February 1, 2009
  9. math

    Can I gt some help on these questions! 1.Research subjects that are divided up based on gender, age, etc. to be compared to people of the same group is what type of design experiment? 2. A biologist collects a sample of 50 snakes. The snakes have a mean

    asked by mysterychicken on June 20, 2013
  10. statistics

    Given a sample size of 38, with sample mean 660.3 and sample standard deviation 95.9 we are to perform the following hypothesis test. Null Hypothesis H0: ƒÊ = 700 Alternative Hypothesis H0: ƒÊ ‚ 700 At significance level 0.05 3. Calculate the test

    asked by Scott on August 9, 2010
  11. Statistics

    This is the first question..... For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3. This is the second question....For each of the following samples that were given an

    asked by Heather on May 3, 2011
  12. statistics

    A specific study found that the average number of doctor visits per year for people over 55 is 8 with a standard deviation of 2. Assume that the variable is normally distributed. 1. Identify the population mean. The population mean is 8. 2. Identify the

    asked by Cameron on June 3, 2013
  13. Statistics

    A population has a mean of   30 and a standard deviation of   5. a. If 5 points were added to every score in the population, what would be the new values for the mean and standard deviation? b. If every score in the population were multiplied by 3 what

    asked by Nickie on January 26, 2013
  14. math

    The standard deviation of a sample taken from population A is 17.6 for a sample of 25. The standard deviation of a sample taken from population B is 21.2 for a sample of 30. The standard deviation of the sample mean differences is_____. (Round your answer

    asked by j on July 15, 2015
  15. Statistics

    hi i need help calculating the standard error using the central limit theorem. *a population of scores contains exactly 5 scores : 2, 3, 6, 8, 11, there are 5x5=25 samples of the two scores (n=2)* i already calculated the standard deviation and mean. for

    asked by ash on November 21, 2010
  16. math

    hi i need help calculating the standard error using the central limit theorem. *a population of scores contains exactly 5 scores : 2, 3, 6, 8, 11, there are 5x5=25 samples of the two scores (n=2)* i already calculated the standard deviation and mean. for

    asked by ash on November 21, 2010
  17. stats

    A sample of 12 observations is selected from a normal population for which the population standard deviation is known to be 4. The sample mean is 19. (Round your answers to 3 decimal places.) (a) The standard error of the mean is The 90 percent confidence

    asked by liam on March 28, 2011
  18. math

    sample of 40 observations is selected from one population with a population standard deviation of 4.6. The sample mean is 101.0. A sample of 47 observations is selected from a second population with a population standard deviation of 4.0. The sample mean

    asked by Phyllis on February 2, 2015
  19. Statistics

    The null and alternate hypotheses are: H0: μ1 = μ2 H1: μ1 ≠ μ2 A random sample of 15 items from the first population showed a mean of 50 and a standard deviation of 5. A sample of 12 items for the second population showed a mean of 46 and a standard

    asked by Anonymous on October 21, 2012
  20. statistics

    sigma is the standard deviation of a population of size N S is the standard deviation of a sample of size n from within the population. What is the estimated value of S^2? If the population was infinitely large (size N = infinity), what would the estimated

    asked by mathstudent on February 21, 2008
  21. statistics

    Describe the major difference between a population of scores with a mean=50, standard deviation=6, and a sample means of n=36 selected from a mean=50, standard deviation=6.

    asked by Nneka on March 9, 2011
  22. Stats

    You take and SRS of size 25 from a population with mean 200 and standard deviation of 10. Find the mean and the standard deviation of the sampling distribution of your sample mean.

    asked by Ryan on July 14, 2011
  23. Psychology/Statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size - 3. Use the formula sqrt(N^ 2/S)

    asked by Dawn on July 15, 2011
  24. statistics

    A researcher administered a treatment to a sample of participants selected from a population of 80. If the researcher obtains a sample mean of M=88. Which combination of factors is most likely to result in rejecting the null hypothesis? a, alpha level=0.01

    asked by Robbie on November 9, 2012
  25. Statistics

    You have a population that has a mean of 100 and a standard deviation of 15. You randomly draw 100 people out of this population and record the mean score. You repeat the process a large number of times recording the mean score for each sample you draw.

    asked by Jared on October 14, 2012
  26. Behavioral Statistics

    You have a population that has a mean of 100 and a standard deviation of 15. You randomly draw 100 people out of this population and record the mean score. You repeat the process a large number of times recording the mean score for each sample you draw.

    asked by Jared on October 14, 2012
  27. statistics

    it is stated that the standard deviation sample of the is 7.6 (n = 26). Test the claim to a significance level of 0.10 that the population standard deviation was greater than 7.0. Round all answers to 3 decimal places.

    asked by geety on July 28, 2012
  28. statistics

    it is stated that the standard deviation sample of the is 7.6 (n = 26). Test the claim to a significance level of 0.10 that the population standard deviation was greater than 7.0. Round all answers to 3 decimal places.

    asked by geety on July 28, 2012
  29. statistics

    An SRS of size n is taken from a large population whose distribution of income is extremely right-skewed and the mean income is calculated. Which of the following statements is false? a) When n > 30, the sampling distribution of is approximately normal. b)

    asked by Anna on April 17, 2012
  30. Stat

    An SRS of size n is taken from a large population whose distribution of income is extremely right-skewed and the mean income is calculated. Which of the following statements is false? a) When n > 30, the sampling distribution of is approximately normal. b)

    asked by Sam on May 6, 2016
  31. Statistics

    If the standard deviation of a population is 56 and we want the standard error (the standard deviation of the sample mean) to be 14, then we need to take how many samples?

    asked by Jana on December 20, 2010
  32. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size - (b) 3 ?.

    asked by net on February 13, 2011
  33. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3.

    asked by mama on April 10, 2011
  34. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3.

    asked by kim on January 24, 2011
  35. stATS

    the standard deviation of the sampling distribution of the means is ____the standard deviation of the population under study.

    asked by tim on November 4, 2011
  36. Statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size 3.

    asked by Barbara on November 15, 2010
  37. Statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3.

    asked by Felicia on November 19, 2010
  38. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3

    asked by amanda on April 4, 2011
  39. psychology

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size - (b) 3 ?.

    asked by net on February 13, 2011
  40. statistics

    population has mean 53 and standard deviation 12. Calculate the standard deviation of x bar for a random sample of size 12.

    asked by Bridget on August 18, 2014
  41. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3.

    asked by Mae on May 12, 2011
  42. Statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size: 3

    asked by Christy on July 4, 2011
  43. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size 3

    asked by melissa on January 10, 2011
  44. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3.

    asked by Anonymous on January 30, 2011
  45. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size 3.

    asked by Reba on June 14, 2011
  46. statistics

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3.

    asked by hope on June 13, 2011
  47. psy325

    For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3

    asked by smith on December 15, 2010
  48. Statistics

    How do you figure this out? For a population that has a standard deviation of 10, what is the standard deviation of the distribution of means for samples of size 2? A-6.33 B-7.07 C-2 D-3.03

    asked by Amanda on May 7, 2010
  49. statistics

    For a population that has a standard deviation of q0, figure the standard deviation of the distribution of means for samples of size-(a)2,(b)3,(c)4,(d)9.

    asked by Dorothy on July 6, 2011
  50. Math1(Please Help Me)

    A group of 894 women aged 70-79 had their height and weight measured. The mean height was 159 cm with a standard deviation of 5 cm and the mean weight was 65.9kg with a standard deviation of 12.7kg. Both sets of data are fairly normal. A.) Suppose you were

    asked by Candice on June 21, 2016
  51. Statistics

    For sample mean x = 150, sample size n = 36 and sample standard deviation s = 40 find 80% confidence interval for population mean. Population standard deviation is not known

    asked by Tina on February 24, 2012
  52. college math

    Math homework please help!! 2. Suppose that people’s weights are normally distributed, with mean 175 pounds and a standard deviation of 6 pounds. Round to the nearest hundredth of a percent a. What percent of the population would weigh between 165 and

    asked by lynda on November 5, 2013
  53. math

    Four boxes of cereal are to be selected at random from a continuous process that fills boxes labeled "Contents: 340 g." The contents of the first three boxes are found to weigh 339.0g, 337.7 g, and 338.9 g. (a) What minimum weight of cereal must the fourth

    asked by david on September 23, 2012
  54. Statistics

    1. A study of 40 people found that they could do on the average15 pull ups with a standard deviation of .6. Find the 99% confidence interval for the mean of the population. 2. A study of 50 pizza delivery workers found that they could make 6 deliveries per

    asked by Anonymous on May 9, 2013
  55. probs & stats

    1. A study of 40 people found that they could do on the average15 pull ups with a standard deviation of .6. Find the 99% confidence interval for the mean of the population. 2. A study of 50 pizza delivery workers found that they could make 6 deliveries per

    asked by adrenning on May 11, 2015
  56. statistics

    poppulation with a mean=100,standard deviation population=10, and n=40. 1) find mean of all values in apoplution. 2) find standard deviation population 3) p(82 LESS THAN 82 less than 97 find mean)

    asked by Anonymous on October 21, 2010
  57. Statistics

    The t distribution should be used when ___. the sampling population is not normal the sampling population is unimodal The sampling distribution is normal and the population standard deviation is unknown the population standard deviation is known

    asked by John on June 22, 2010
  58. Statisitcs

    The mean height of fully grown birch trees are 18 feet with a standard deviation of 1.2 feet, normally distributed. Random samples of size 9 are drawn from this population and the mean of each sample is determined. Find that mean and the standard error of

    asked by D on November 14, 2012
  59. Algebra

    Use a calculator to find the mean and standard deviation of the data. Round to the nearest tenth. 6,7,19,7,18,7 A. mean = 9; standard deviation = 26.4 B. mean = 11.9; standard deviation = 26.4 C. mean = 10.6; standard deviation = 6.1 D. mean = 9; standard

    asked by Veronika on February 18, 2016
  60. business statistics

    A sample of 40 investment customers serviced by an account manager are found to have had an average of $23,000 in transactions during the past year, with a standard deviation of $8500. A sample of 30 customers serviced by another account manger averaged

    asked by Heidi on August 4, 2009
  61. Stats

    I just need help with starting how to calculate the problem I am so lost. A random sample of eight observations from the first population resulted in a standard deviation of 10. A random sample of six observations from the second population resulted in a

    asked by Yasmin on December 6, 2010
  62. Statistics/Probability

    The standard deviation of the masses of articles in a large population is 4.55 kg. Random samples of size 100 are drawn from the population. Find the probability that a sample mean will differ from the population mean by less than 0.8 kg.

    asked by Koylar on July 17, 2014
  63. statistics

    A sample of 40 observations is selected from one approximately normal population. The sample mean is 102 and the sample standard deviation is 5. A sample of 50 observations is selected from a second source. The sample mean is 99 and the standard deviation

    asked by K on May 22, 2010
  64. statistics

    A sample of 40 observations is selected from one approximately normal population. The sample mean is 102 and the sample standard deviation is 5. A sample of 50 observations is selected from a second source. The sample mean is 99 and the standard deviation

    asked by georgia on May 29, 2010
  65. statistics

    5) The lifetime of a medical device s a normally distributed rv with standard deviation of 2 years. An experiment is conducted to test 15 medical devices and find their lifetimes to be: a. If the population mean is known to be 15 years, what is the

    asked by nur on December 8, 2012
  66. statistics

    What is the formula to do this exercise, Please. A sample of 40 investment customers serviced by an account manager are found to have had an average of $23,000 in transactions during the past year, with a standard deviation of $8500. A sample of 30

    asked by Maggy on August 9, 2009
  67. business statistics

    Please can you give the formula please, A sample of 40 investment customers serviced by an account manager are found to have had an average of $23,000 in transactions during the past year, with a standard deviation of $8500. A sample of 30 customers

    asked by Heidy on August 9, 2009
  68. Statistics

    Suppose that a sample of size 60 is drawn from a population with mean 73 and standard deviation 79. Find the value of , the standard deviation of the distribution of sample means. How do I work this on my calculator?

    asked by Anonymous on June 18, 2013
  69. Statistics

    QUESTION 1 Use the following scenario and data for all the questions The lives of Lithium batteries used in a type of cell phones are normally distributed with an unknown standard deviation. A simple random sample of equation batteries is selected. The

    asked by Neyra on October 31, 2017
  70. business statistics

    Please can you give the formula to do this exercise, Thank you. A sample of 40 investment customers serviced by an account manager are found to have had an average of $23,000 in transactions during the past year, with a standard deviation of $8500. A

    asked by Heidy on August 10, 2009
  71. Statistics

    A college statistics class conducted a survey of how students spend their money. They asked 25 students to estimate how much money they typically spend each week on fast food. They determined that the mean amount spent on fast food is $31.52 with a

    asked by sam on October 14, 2016
  72. statistics

    A sample of 40 CDs from a student's collection showed a mean length of 52.74 minutes with a standard deviation of 13.21 minutes. Construct a 95% confidence interval for the population standard deviation. (Round your answers to 4 decimal places.)

    asked by Anonymous on June 26, 2014
  73. Math

    Roughly speaking, the standard deviation indicates how far, on average, the observations are from the mean. Do you think that for the data set below the standard deviation will give a good indication of the typical deviation from the mean? 2, 3, 4, 4, 5,

    asked by Lyndse on February 21, 2010
  74. stats

    The president of a large university wishes to estimate the average age of the students presently enrolled. From past studies, the standard deviation ó is known to be 2 years. A sample of 50 students is selected and the mean is found to be 23.3 years. a.

    asked by chris on April 7, 2013
  75. Psychology

    Twenty students randomly assigned to an experimental group receive an instructional program; 30 in a control group do not. After 6 months, both groups are tested on their knowledge. The experimental group has a mean of 38 on the test (with an estimated

    asked by Anonymous on September 23, 2010
  76. Statistic

    Twenty students assigned to an experimental group receive 30 in a control group has a mean of 38 on the test (with an estimated population standard deviation of 3); the control group has a mean of 35 (with an estimated population standard deviation of 5).

    asked by Anonymous on October 10, 2009
  77. Math--Statistics

    Two questions that I'm unsure of are below: 1). The variability of a statistic is described by: a) the spread of its sampling distribution. b) the amount of bias present c) the vagueness in the wording of the question used to collect the sample data d) the

    asked by Anonymous on March 15, 2011
  78. Statistics

    I have a question that involves explaining what is wrong in each of the following situations: (a) A random sample of size 20 is taken from a population that is assumed to have a standard deviation of 12. The standard deviation of the sample mean is 12/20.

    asked by Lynn on March 29, 2009
  79. Psychology

    Twenty students randomly assigned to an experimental group receive an instructional program; 30 in a control group do not. After 6 months, both groups are tested on their knowledge. The experimental group has a mean of 38 on the test (with an estimated

    asked by summer on September 19, 2011
  80. Statistics

    1) A Motor Company has purchased steel parts from a supplier for several years and has found that 10% of the parts must be returned because they are defective. An order of 25 parts is received. What are the mean and standard deviation of the defective

    asked by BEARHUG on February 15, 2009
  81. statistics

    A population has a mean =80 and a standard deviation =8. find the mean and standard deviation of a sampling distribution of sample means with sample size=64

    asked by antorio on February 12, 2013
  82. statistics

    a population has mean 15 and standard deviation 5. if 68% of the values in the population are between 10 and 20, the population cannot be normal

    asked by nikki on July 11, 2011
  83. statistics

    Consider the test of hypothesis for the equality of two population means. The sample data from the first population is: n = 10, x-bar = 52.4, s = 5. The sample data from the second population is: n = 8, x-bar = 48.2, s = 6. Both variables are normally

    asked by Anonymous on March 27, 2015
  84. statistics

    A statistics practitioner would like to estimate a population mean to within 50 units with 99% confidence given that the population standard deviation is 250. a) What sample size should be used. b) Repeat part (a) with a standard deviation of 50. c) Repeat

    asked by Tom on March 13, 2010
  85. statistics

    A study found that citizens spend on average $1950 per year on groceries with a standard deviation of $100. Assume that the variable is normally distributed. 5. Identify the population mean. 6. Identify the population standard deviation. 7. Find the

    asked by Cam on April 19, 2013
  86. statistics

    Assume the population distribution of FEV is normal with standard deviation 400 mLi. (a) find P(E) is n=15 and population mean is 2800 mLi (B) find P(E) is n=15 and the population mean is 2600mLi (C) How does P(E) depend on the population mean?

    asked by Sam on October 13, 2009
  87. Statistics

    If the standard deviation of a sample is 4.3 for 28 data values, what would the standard deviation be fore the population from which the sample was drawn?

    asked by Leisa on January 30, 2013
  88. Math

    Repeated sample of 36 are drawn from a population with mean 52 and standard deviation 18. What is the standard deviation of the distribution of the sample means?

    asked by Lori on March 28, 2011
  89. statistics

    You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 5 and a population standard deviation 1 and a sample size of 4. Machine 2 has a sample mean of 8 and a population standard deviation of 2 with a

    asked by Anonymous on October 11, 2010
  90. STAT

    You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 5 and a population standard deviation 2 and a sample size of 4. Machine 2 has a sample mean of 10 and a population standard deviation of 2 with a

    asked by Tammy on October 7, 2013
  91. statistics

    A statistics practitioner formulated the following hypothesis: Ho: population mean=200 H1: population mean

    asked by Adam on March 19, 2010
  92. Business

    For a continuous random variable x, the population mean and the population standard deviation are 80 and 15 respectively. You extract a sample of 25 elements from this population. The mean of the sampling distribution of the sample mean is

    asked by Donna on May 16, 2010
  93. Statistic

    Twenty students assigned to an experimental group receive 30 in a control group has a mean of 38 on the test (with an estimated population standard deviation of 3); the control group has a mean of 35 (with an estimated population standard deviation of 5).

    asked by Anonymous on October 11, 2009
  94. statistics

    An IQ test was administered to a random sample of 26 mental patients and the mean was found to be 99.7. For this test, the population values are known to be normally distributed and with a population standard deviation of 15. Construct a 90% confidence

    asked by Anonymous on December 18, 2014
  95. math

    A medical researcher wants to determine whether male pulse rates vary more or less than female pulse rates. Using the sample pulse rates in Data Set 1 in Appendix B, the male pulse rates can be summarized with the statistics 40=n,69.4=x,11.3=s. For

    asked by josh on November 27, 2017
  96. statistics

    Suppose a population distribution of SAT scores has population mean 500 and population standard deviation 100. What is the mean of the sampling distribution of sample means, ybar , calculated from samples of size n = 36

    asked by Emmily on November 11, 2011
  97. statistics

    A sample of 25 men has a mean weight of 65kg with standard deviation of 8kg. Suppose that the weight of men follows normal distribution with a standard deviation of 10kg. Find a 95% confidence interval for the population mean μ.

    asked by Ali on June 3, 2011
  98. Statistics

    Scores on an IQ test are normally distributed. A sample of 15 IQ scores had standard deviation s=10. The developer of the test claims that the population standard deviation is =15. Do these data provide sufficient evidence to contradict this claim? Use

    asked by steph on March 12, 2019
  99. statistics

    How large a sample should be taken if the population mean is to be estimated with 99% confidence to within $75? The population has a standard deviation of $900.

    asked by Kabelo on April 15, 2018
  100. statistics

    How large a sample should be taken if the population mean is to be estimated with 99% confidence to within $72? The population has a standard deviation of $800.

    asked by Kennon on November 18, 2008