statistics

The average one-way commute time for a random sample of 256 area residents of a city is 90 minutes, with a standard deviation of 24 minutes.

Construct a 90% confidence interval for the mean commute time of all residents.
Construct a 98% confidence interval for the mean commute time of all residents.
Which interval is larger? Why?

  1. 👍 0
  2. 👎 0
  3. 👁 255
asked by tee jay
  1. Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (for two-tailed, .05 and .01) and get the respective Z scores.

    90% = Mean ± Z(SD)

    98% = mean ± Z(SD)

    After the calculations, you should be able to answer why.

    1. 👍 0
    2. 👎 0
    posted by PsyDAG

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math

    1.)Suppose you interview 10 randomly selected workers and ask how many miles they commute to work. You'll compute the sample mean commute distance. Now imagine repeating the survey many, many times, each time recording a different

    asked by Elie on March 16, 2011
  2. Math--Statistics

    I have a couple of questions that need review--I've answered them, but I'm not sure if I'm correct. 1.)Suppose you interview 10 randomly selected workers and ask how many miles they commute to work. You'll compute the sample mean

    asked by Anonymous on March 15, 2011
  3. AP Stats (math)

    A large metropolitan area found that the time it takes for people to commute to work has a mean of 20.5 minutes and a standard deviation of 15.4 minutes. What is the probability that a random sample of 40 people have a mean

    asked by Kyle on April 7, 2013
  4. statistics

    If the average commute time is 10.9 miles, but the average is actually the mean of a sample of 300 commuters and the sample standard deviation is 6.2 miles Estimate the true mean commute distance using 99% confidence level.

    asked by Mel on November 23, 2013
  5. Algebra 1

    A city planning committee surveys 100 people waiting at a bus stop about the expansion of the public transportation system. Is this an example of a: random sample, systematic sample, self-selected sample, convenience sample,

    asked by Natalia on January 13, 2017
  6. Algebra 1

    Can you please check my work? A city planning committee surveys 100 people waiting at a bus stop about the expansion of the public transportation system. Is this an example of a: random sample, systematic sample, self-selected

    asked by Caroline on April 27, 2014
  7. stats

    I am having a bit of trouble with the top half of the questions. I have an answer below for questions 5-10, is there anyway you can check those answers and help me with the rest I am having trouble with. Thank you. 1. The area to

    asked by sandra on July 22, 2013
  8. college statistics

    I am having a bit of trouble with the top half of the questions. I have an answer below for questions 5-10, is there anyway you can check those answers and help me with the rest I am having trouble with. Thank you. 1. The area to

    asked by penelope on July 18, 2013
  9. Quantitative Methods II

    The monthly income of residents of Daisy City is normally distributed with a mean of $3000 and a standard deviation of $500. a. What is the random variable? b. The mayor of Daisy City makes $2250 a month. What percentage of Daisy

    asked by Chrystal on March 19, 2009
  10. Quantitative Methods

    The monthly income of residents of Daisy City is normally distributed with a mean of $3000 and a standard deviation of $500. a. What is the random variable? b. The mayor of Daisy City makes $2250 a month. What percentage of Daisy

    asked by V on March 19, 2009

More Similar Questions