Statistics

posted by .

1) A sample of 49 observations is taken from a normal population. The sample mean is 55 and the sample standard deviation is 10. Determine the 99% confidence interval for the population mean.

2) The Fox TV network is considering replacing one of its primetime crime investigation shows with a new family-oriented comedy show. Before a final decision is made, network executives commission a sample of 400 viewers. After viewing the comedy, 250 indicated they would watch the new show and suggested it replace the crime investigation show.

A) Estimate the value of the population proportion.
B) Compute the standard error of the proportion.
C) Develop a 99% CI for the population proportion.
Interpret your findings.

  • Statistics -

    1) Formula using 99% confidence interval:

    CI99 = mean ± (2.58)(sd/√n)

    Note: ± 2.58 represents 99% confidence interval.

    mean = 55
    sd = 10
    n = 49

    Plug the values into the formula and calculate.

    2) Formula for 99% interval estimate of the population proportion:

    CI95 = p + or - 2.58[√(pq/n]

    p = 250/400
    q = 1 - p
    n = 400

    Convert the fractions to decimals, substitute the decimals into the formula, then finish the calculation.

    A) and B) can be answered using the information above.

    I hope this will help get you started.

  • Correction -

    For 2), the formula should read:

    CI99 = p + or - 2.58[√(pq/n)]

    Sorry for any confusion.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. statistics

    7. A sample of 40 observations is selected from one population. The sample mean is 102 and the sample standard deviation is 5. A sample of 50 observations is selected from a second population. The sample mean is 99 and the sample standard …
  2. Statistics

    8. A sample of 65 observations is selected from one population. The sample mean is 2.67 and the sample standard deviation is .75. A sample of 50 observations is selected from a second population. The sample mean is 2.59 and the sample …
  3. 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 …
  4. 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 …
  5. 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 …
  6. statistics

    A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is 15. a) Compute the 95 % confidence interval for the population mean. b) Assume that the same sample mean was obtained from a sample …
  7. statistics

    Determine the 90% confidence interval for a sample, taken from a normally distributed population, that has a mean of 685, a sample standard deviation of 74, and a sample size of 29
  8. statistics

    Determine the 90% confidence interval for a sample, taken from a normally distributed population, that has a mean of 685, a sample standard deviation of 74, and a sample size of 29
  9. Research and Evaluation

    1) A sample of 49 observations is taken from a normal population. The sample mean is 55 and the sample standard deviation is 10. Determine the 99% confidence interval for the population mean. 2) The Fox TV network is considering replacing …
  10. Statistics (42)

    A simple random sample of 60 items resulted in a sample mean of 96. The population standard deviation is 16. a. Compute the 95% confidence interval for the population mean (to 1 decimal). ( , ) b. Assume that the same sample mean was …

More Similar Questions