1. A population consists of the following four values 12,12,14 and 16
    a.    List all sample of size 2, and compute the mean of each sample
    b.    Compute the mean of the ditribustion of the sample mean and the population mean. Compare the two values
    c.    Compare the dispersion in the population with that of that sampel mean
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.270., exercise 5) soal jawab distribusi sampling no 1 
  2.  Scrapper Elevator company has 20 sales represenattive who sell its product through out of the United states and Canada. The number of units sold last month by each representative is listed below. Assume these sales figure to be the population values
    2          3          2          3          3          4          2          4          3          2          2          7          3          4          5          3          3          3          3          5 

    a.    Draw a graph showing the population distribution
    b.    Compute the mean of the population
    c.    Select five random samples of 5 each. Compute the mean of each sample. Use the methods described in this chapter and Appendix B.6 to determine the item to be incluede in the sample
    d.     Draw a histogram of the sample means. Do you notice a difference in the shape od the distribution of the sample means compare to the shape of the populatuion distribution?
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.278., exercise 13) soal jawab distribusi sampling no 2
     

  3.  A normal distribution has a mean of 60 and a standard deviation of 12. You select a random sample of 9, compute the probability the sample mean is,
    a.    Greater than 63
    b.    Less than 56
    c.    Between 56 and 63
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.281., exercise 15) soal jawab distribusi sampling no 3 
  4.  According to an IRS study, it takes a mean of 330 minutes for taxprayer to prepare, to copy and electronically file of 1040 tax form. This distribution of time follows the normal distribution and the standard deviation is 80 minutes. A consumer watchdog agency select a random samples of 40 taxprayers
    a.    What is the standar error of the mean in the example
    b.    What is the likelihood the sample mean is greater than 320 minues
    c.    What is the likelihood the sample mean is between 320 and 350 minutes
    d.    What is the likelihood the sample mean is greater than 350 minutes
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.281., exercise 18) soal jawab distribusi sampling no 4 
  5.  Sebuah populasi terhingga terdiri atas 2, 2, 4, 6 dan 6
    (a)  Bila ke 25 kemungkinan comtoh berukuran 2 yang diambil dengan pemulihan mempunyai kemungkinan terjadi yang sama, susunlah sebaran penarikan contoh bagi
    (b)  Susun histogram peluang bagi sebaran penarikan contoh diatas
    (c)  Verifikasi bahwa  dan
    (Ronald E Walpole., Pengantar Statistika., Gramedia Pustaka Utama, Edisi ke 3., halaman 226, Soal-soal latihan no 3) soal jawab distribusi sampling no 5 
  6. In the Department of Education at UR University, student records suggest that the population of students spends an average of 5.5. hours per week playing organized sports. The population’s standard deviation is 2.2 hours per week. Based on sample of 121 students, Healthy lifestyles incorporated (HLI) would like to apply the central rheore to make various estimates.
    a.    Compute the standar error of sample mean
    b.    What is the chance HLI will find a sample mean between 5 and 6 hours?
    c.    Calculate the probability that the sample will be between 5.3 and 5.7 hours?
    d.    How strange would it be to obatin a sample mean greater than 6.5 hours?
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.278., exercise 13) soal jawab distribusi sampling no 6 
  7.  Answer the following questions in one or two well constructed sentences.
    a.    What happenes to the standard error of the mean if the sample size is increased?
    b.    What happenes to the distribution of sample means if the sample size is increased?
    c.    When using the distribution of the sample means to estimate the population mean, what is the benefit of using larger sample size?
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.283., exercise 24) soal jawab distribusi sampling no 7 
  8.  At the downtown office of First National Bank there are five tellers. Last week the tellers made the folllowing number of errors each, : 2, 3, 5, 3 and 5
    a.    How many different samples of 2 tellers are possible
    b.    List all possible samples of two telles are possbile
    c.    Compute the mean of the samples means and compare to the population mean
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.284., exercise 28) soal jawab distribusi sampling no 8 
  9. The appliance Centre has six sales representatives at the North, jacksonville outlet. Listed below the number of refrigators sold by each last month
    a. How many samples of size two are possble
    b.    Select all possible samples of size 2 and compute the mean sumber sold
    c.    Organioze the sample means into afrequancy distribution
    d.   What is the mean of the population ? What is the meman of the sample means?
    e.    What is the shape of the population distribution ?
    f.     What is the shape of the distribution of the sample mean?
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.284., exercise 30) soal jawab distribusi sampling no 9 
  10. CRA CDs, Inc wants the meman lengths of the ”cuts” on CD to be 135 seconds ( 2 minutes and 15 seconds). This will allow the disk jockes to have a plenty of time for commercials withi each 10 minute segment. Assume the distribution of the length of the ”cuts” follows the normal distribution with a population standard deviation of 8 seconds. Suppose we select a sample of 16 ”cuts” from various CDs sold by CRA SDs, Inc.
    a.    What can we say about the shape of the distribution of the sample mean
    b.    What is the standard error of the mean
    c.    What percent of the sample means will be greater than 140 seconds
    d.    What percent of the sample means will be greater than 128 seconds
    e.    What percent of the sample means will be greater than 128 seconds but less han 140 seconds
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.285., exercise 32) soal jawab distribusi sampling no 10 
  11. 11.  Information from the American Instituite of Insurance Indicates the mean amount of the insurance per household in the United States is $ 110,000. The ditribution follows the normal distribution with a standard deviation of $ 40,000
    a.    If we select a ramdon sample of 50 households, what is standard error of the mean?
    b.    What is the expected shape of the distribution of the sample mean
    c.    What is the likelihood of the selecting a sample with a mean of at least $112,000
    d.    What is the likelihood of the selecting a sample with a mean of more than  $100,000
    e.    Find the likelihood of selecting a sample with a measn of more than $100,000 but less than $112,000
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.285., exercise 34) soal jawab distribusi sampling no 11 
  12.  A recent study by Greate Los Angeles Taxi Drivers Association showed that the mean fare charged for service from Hermosa Beach to Los Angeles International airport is $18.00 and the standard deviation is $3.50. We select of 15 fares,
    a.    What is the likelihood that the sample mean is between $17.00 and $ 20.00
    b.    What must you assume to make the above calculation
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.285., exercise 36) soal jawab distribusi sampling no 12 
  13. The mean mount purchased by a typical customer at Churchill’s Grocery store is $23.50 with a standar deviation of $5.00. Assume the distribution orf amounts purchased follow the normal distribution. For a sample of 50 customers, answer the following questions
    a.    What is the likelihood the sample mean is at least $ 25.00
    b.    What is the likelihood the sample mean is greater than $22.50 but less than  $ 25.00
    c.    Within what limits will 90 percent of the sample means occur?
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.285., exercise 38) soal jawab distribusi sampling no 13 
  14.  Suppose we roll a fair die two times
    a.    How many different sample are there?
    b.    List of the possible sample and compute the mean ?
    c.    On a chart similiar to chart 8-1 compare the distribution of sample means with the distribution of the population
    d.    Compute the mean and the standard deviation of each distribution and compare them
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.286., exercise 40) soal jawab distribusi sampling no 14 
  15.  Human Resouces Counting (HRC) is surveying a sample of 60 items in door to study health care costs for a client. One of the items being tracked is the annual deductible that employees must pay. Tha state of labor reports the mean of the distribution is $ 502 with a standard deviation of $ 100.
    a.    Compute the standard error of the sample mean for HRC
    b.    What is the chance HRC finds a sample mean between $ 477 and $527 ?
    c.    Calculate the likelihood that the sample mean is between $ 492 and $ 512
    d.    What is the probability the sample mean is greater than $550
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., MsGraw Hill., Fourteen Edition., p.286., exercise 42) soal jawab distribusi sampling no 15 
  16. The Oil Price Information Centre reports the mean price per gallon of regular gasoline is $ 3.70 with a population stanadard deviation of $ 0.18. Assume a random sample of 40 gasoline stations is selcted and their mean cost for regular gasoline is computed
    a.    What is the standard error of the mean in this experiment
    b.    What is the probability that the sample mean is between $3.77 and $ 3.81 ?
    c.    What is the probability that the different between the sample mean and the population mean is less than 0.01 ?
    d.    What is the likelihood the sample mean is greater than $3.87
    (Lind, Marchal, Warhern., Statistical Technique in Business and Economics., McGraw Hill., Fourteen Edition., p.287., exercise 44) soal jawab distribusi sampling no 16

 

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