Question

4) On a standard IQ test, σ = 15. How many random IQ scores must be...

4) On a standard IQ test, σ = 15. How many random IQ scores must be obtained if we want to find the true population mean, with an allowable error of 0.5 and we want 99% confidence in the results?

5) Given n = 25, s = 15, and α = 0.01, find the maximum error of estimate, E.

Homework Answers

Answer #1

4)

Given that,

Population standard deviation = = 15

Margin of error = E = 0.5

Z/2 = 2.576

sample size = n = [Z/2* / E] 2

n = [2.576 * 15 / 0.5]2

n = 5973

Sample size = n = 5973

5)

t /2,df = 2.797

Margin of error = E = t/2,df * (s /n)

= 2.797 * (15 / 25)

Margin of error = E = 8.391

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
Suppose we know that the population standard deviation for wages (σ) is $15. A random sample...
Suppose we know that the population standard deviation for wages (σ) is $15. A random sample of n = 900 results in a sample mean wage of $50. (10 points) Provide 95% confidence interval estimate of µ. Interpret the result. What is the value of the margin of error? Provide 90% confidence interval estimate of µ. What is the value of the margin of error? Provide 99% confidence interval estimate of µ. What is the value of the margin of...
Suppose we know that examination scores have a population standard deviation of σ = 25. A...
Suppose we know that examination scores have a population standard deviation of σ = 25. A random sample of n = 400 students is taken and the average examination score in that sample is 75. Find a 95% and 99% confidence interval estimate of the population mean µ.
A psychologist wants to estimate the standard deviation of IQ scores. It is widely believed that...
A psychologist wants to estimate the standard deviation of IQ scores. It is widely believed that IQ scores follow a normal distribution. Her random sample of 25 IQ scores has a mean of 99 and a standard deviation of 13.2 . Find the 99% confidence interval for the population standard deviation based on this sample. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your answers to at least two decimal places. (If...
A psychologist wants to estimate the standard deviation of IQ scores. It is widely believed that...
A psychologist wants to estimate the standard deviation of IQ scores. It is widely believed that IQ scores follow a normal distribution. Her random sample of 25 IQ scores has a mean of 97.4 and a standard deviation of 17.2. Find the 99% confidence interval for the population standard deviation based on this sample. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your answers to at least two decimal places. (If necessary,...
4.2. Q: In a study on a 99% confidence interval on IQ scores (Data with mean...
4.2. Q: In a study on a 99% confidence interval on IQ scores (Data with mean µ =100 and standard deviation σ = 15), the researcher would like to achieve a margin error of 3 IQ score units. Find the number, n, of IQ scores that should be sampled to achieve that error? Answer: A: 120; B: 166; C: 97; D: 216
The standard IQ test is designed so that the mean is 100 and the standard deviation...
The standard IQ test is designed so that the mean is 100 and the standard deviation is 15 for the population of all adults. We wish to find the sample size necessary to estimate the mean IQ score of all people who have successfully passed a college statistics course. We want to create a confidence interval that is no wider than 8 IQ points. The standard deviation for this sub-population is certainly less than 15 as it should be a...
Assume that we want to estimate the mean IQ score for the population of statistics students....
Assume that we want to estimate the mean IQ score for the population of statistics students. How many statistics students must be randomly selected for IQ tests if we want 95% confidence that the sample mean is within 2 IQ points of the population mean? Assume that σ = 15. Round the answer to the nearest large whole number!
An IQ test is designed so that the mean is 100 and the standard deviation is12...
An IQ test is designed so that the mean is 100 and the standard deviation is12 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 99​% confidence that the sample mean is within 3 IQ points of the true mean. Assume that σ=12 and determine the required sample size using technology. Then determine if this is a reasonable sample size for a...
IQ scores follow a Normal distribution with a mean μ = 100 and standard deviation σ...
IQ scores follow a Normal distribution with a mean μ = 100 and standard deviation σ = 15. A SRS of 31 seventh-grade girls in one school district is tested and the sample mean x¯¯¯x¯ was = 102 . Is there evidence that the mean IQ score in this district is different from from 100? The alternative hypothesis is: Ha: u < 100 Ha: u > 100 Ha: u ≠ 100 The test statistic, z =....... (+ 0.01) P(z )...
An IQ test is designed so that the mean is 100 and the standard deviation is...
An IQ test is designed so that the mean is 100 and the standard deviation is 12 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 99​% confidence that the sample mean is within 5 IQ points of the true mean. Assume that σ =12 and determine the required sample size using technology. Then determine if this is a reasonable sample size...