statistics

The following random sample was collected: 22 33 44 6. The 80% confidence interval for the mean is?
I have the answers; however, I do not know how to plug in the numbers to solve the problem.

  1. 👍 0
  2. 👎 0
  3. 👁 106
asked by Nicole
  1. The sample is too small for a confidence interval to be really meaningful.

    Find the mean first = sum of scores/number of scores

    Subtract each of the scores from the mean and square each difference. Find the sum of these squares. Divide that by the number of scores to get variance.

    Standard deviation = square root of variance

    Z = (score-mean)/SEm

    SEm = SD/√n

    Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.40) and its Z score.

    Plug that ±Z score into the equation above.

    I'll let you do the calculations.

    1. 👍 0
    2. 👎 0
    posted by PsyDAG

Respond to this Question

First Name

Your Response

Similar Questions

  1. stat

    7. A researcher selects a random sample. A 90% confidence interval for a population mean  A) is an interval with margin of error ± 90%. B) has the property that if we repeatedly selected our random sample in exactly the same

    asked by Anonymous on December 5, 2010
  2. Math-Stat Help

    In a random sample of 78 teenagers, 32 admit to texting while driving. Construct a 98% confidence interval for the percentage of teenager that text while driving. Start by showing that conditions for constructing a confidence

    asked by MELISSA on April 11, 2013
  3. MATH

    A random sample of size 81 has sample mean 20 and sample standard deviation 3. (a) Is it appropriate to use a Student’s t distribution to compute a confidence interval for the population mean μ? Explain. (b) Find a 95%

    asked by Anonymous on April 4, 2019
  4. Statistics

    When consumers apply for credit, their credit is rated using the FICO score. A bank manager used a random sample of the credit scores of 18 customers and determined the following 95% confidence interval: (613.6, 708.0) If the

    asked by Katelyn on November 6, 2013
  5. Statistics

    5. A random sample of size 81 has sample mean 20 and sample standard deviation 3. (a) Is it appropriate to use a Student’s t distribution to compute a confidence interval for the population mean μ? Explain. (1 mark) (b) Find a

    asked by Anonymous on April 4, 2019
  1. Statistics

    Hoping to lure more shoppers downtown, a city builds a new parking garage in the central business district. The city hopes that the parking revenues will pay for the garage. During a recent two month period (44 days), the city

    asked by Katie on November 10, 2013
  2. Statistics

    A 95% confidence interval for a population mean, ?, is given as (18.985, 21.015). This confidence interval is based on a simple random sample of 36 observations. Calculate the sample mean, x ?, and the sample standard deviation,

    asked by Mike on June 18, 2012
  3. Statistics

    Suppose x has a mound-shaped distribution with sigma = 9 . A random sample of size 36 has sample mean 20. Is it appropriate to use a normal distribution to compute a confidence interval for the population mean m? Explain. Find a

    asked by Steph on April 27, 2013
  4. statistics

    1. A random sample of size 49 is taken from a large population, measuring the time it takes to complete a driver’s license examination. The sample mean was found to be 47 minutes, and the sample standard deviation 5.89 minutes.

    asked by Anonymous on July 17, 2010
  5. Statistics

    Which of the following statements best describes the uncertainty associated with a 95% confidence interval for a population proportion, computed from a simple random sample? A. We don't know whether the particular confidence

    asked by Mary on May 18, 2012

More Similar Questions