# Suppose I am using the t-distribution to estimate or test the mean of a sample from a single population. If the sample size is 25, then the degrees of freedom are ____?

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### Statistics

Suppose I am using the t-distribution to estimate or test the mean of a sample from a single population. If the sample size is 25, then the degrees of freedom are ____? I have an answer of 26 is this correct

### statistics

Suppose we take a random sample of size n from a normal population with variance, σ2 . It can be shown that (n−1)s2/σ2 has a chi-square distribution with n−1 degrees of freedom, where s is the sample variance. Below is a random sample of size 8 drawn from...

### Statistics

You are interested in estimating the mean of a population. you plan to take a random sample from the population and use the samples mean as an estimate of population mean. Assuming that the population from which you select your sample is normal, which of the statements about ...

### Statistics

Kind attention Psydag: A random sample of size 20 from a normal population with sample mean 42 and sample standard deviation of 6 . To test the hypothesis the population mean 44 at 5% level of significance , find the p-value and comment Clarification: The sample size is 20 ...

### Math (Statistic)

Considered the sampling distribution of a sample mean obtained by random sampling from an infinite population. This population has a distribution that is highly skewed toward the larger values. a) How is the mean of the sampling distribution related to the mean of the ...

### Statistics

An IQ test is designed so that the mean is 100 and the standard deviation is 19 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 95% confidence that the sample mean is within ...

### sample size/ standard deviations

How do we compute sample size fluctuations? Suppose we have a population of 16000 and a sample size of 30, and the number of samples 1000, what will be the impact on population mean and standard deviation when the population is normally distributed? When the population is ...

### statistics

An IQ is designed so that the mean is 100 and the standard deviation is 23 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 90% confidence that the sample mean is within 5 IQ ...

### statistics

historically, the average customer spends $8.53 for all TGP restaurants(u=8.53). If the population standard deviation is $1.06(o=1.06) and the data is normally distributed, find the probabiltiy that the sample mean will be within $.15 of the populaiton mean using a sample size...

### Bcc

suppose x has a mound-shaped distribution. A random sample size 16 has a sample mean of 10 and a sample standard deviation of 2. Find 99% cinfidence interval for mue (mean) using a student's t distribution.

### statistics

How do we compute sample size fluctuations? Suppose we have a population of 16000 and a sample size of 30, and the number of samples 1000, what will be the impact on population mean and standard deviation when the population is normally distributed? When the population is ...

### Statistics

Calculate the following: a) Determine the sample size necessary to estimate a population mean to within 1 with a 90% confidence given that the population standard deviation is 10. b) Suppose that the sample was calculated at 150. Estimate the population mean with 90% confidence.

### statistics

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

### statistics

A population has a mean of 300 and a standard deviation of 50. Suppose a sample of size 125 is selected and is used to estimate . What is the probability that the sample mean will be within +/- 3 of the population mean (to 4 decimals)?

### sda high

A population has a mean of 200 and a standard deviation of 50. Suppose a simple random sample of size 100 is selected and is used to estimate μ. What is the probability that the sample mean will be within 5 of the population mean?

### Statistics

This is the first question..... For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3. This is the second question....For each of the following samples that were given an experimental ...

### statistics

what are the mean and standard deviation of a sampling distribution consisting of samples of size 16? these sameples were drawn from a population whose mean is 25 and who standard deviation is 5. a. 25 and 1.25 b. 5 and 5 c. 25 and 5 d. 5 and 1.25 e. 25 and square root of 5 ...

### Statistic

A random sample of size 20 drawn from a normal distribution has a sample mean of 8 and a sample standard deviation of 4. A) Compute the sample test statistic t under the null hypothesis H_0: Mue(mean)=7 B) State the alternate hypothesis if you believe that the population mean ...

### statistics

The scores of students on the ACT college entrance examination in a recent year had a normal distribution with a mean of 18.6 and a standard deviation of 5.9. A simple random sample of 50 students who took the exam is selected for study: A) What is the shape, mean, and ...

### Statistics

. A random sample is selected from a normal population with a mean of __40 and a standard deviation of __10. After a treatment is administered to the individuals in the sample, the sample mean is found to be M _ 42. a. How large a sample is necessary for this sample mean to be...

### Probabilty & Statistic

A random sample is selected from a normal population with a mean of __40 and a standard deviation of __10. After a treatment is administered to the individuals in the sample, the sample mean is found to be M _ 42. a. How large a sample is necessary for this sample mean to be ...

### Math

When using the student's t distribution to test mu, what value do you use for the degrees of freedom if the sample size is 42? a. 41 b. Can not be determined from information given. c. 43 d. 42

### statistics

Suppose a population distribution of SAT scores has population mean 500 and population standard deviation 100. What is the mean of the sampling distribution of sample means, ybar , calculated from samples of size n = 36

### statistics

Scores on a certain test are normally distributed with a variance of 14. A researcher wishes to estimate the mean score achieved by all adults on the test. Find the sample size needed to assure with 95% confidence that the sample mean will not differ from the population mean ...

### Statistics

In a study to estimate a population mean, i start with a sample size 10 and calculate the 95% confidence interval. Suppose i am not satisfied with the size of the confidence interval and want to reduce it by half. Give an estimate of sample size that i need.

### statistics

Scores on a certain test are normally distributed with a variance of 91. A researcher wishes to estimate the mean score achieved by all adults on the test. Find the sample size needed to assure with 95.44 percent confidence that the sample mean will not differ from the ...

### Math- Statistics

A random sample of size 36 is to be selected from a population that has a mean μ = 50 and a standard deviation σ of 10. * a. This sample of 36 has a mean value of , which belongs to a sampling distribution. Find the shape of this sampling distribution. * b. Find the ...

### Statistics

Suppose that a sample of size 58 is drawn from a population with mean 23 and standard deviation 80. Find the value of , the mean of the distribution of sample means. Wrtie only a number as your answer.

### Statistics

The following is a histogram (right skewed) of the first ten terms of a geometric distribution with p = .4. The mean of this distribution is 2.5 and the standard deviation is approximately 1.93. What's the shape of the distribution of sample means for simple random samples of ...

### statistics

Use the given information to find the minimum sample size required to estimate an unknown population mean u. How many adults must be randomly selected to estimate the mean FICO (credit rating)score of working adults in a country? We want 95% confidence that the sample mean is ...

### 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 deviation is 6. Conduct the following ...

### 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 standard deviation is .66. Conduct the ...

### Statistics

A random sample of size 20 from a normal population will sample mean 42 and sample standard deviation of 6 . To test the hypothesis the population mean 44 at 5% level of significance , find the p-value and comment

### statistics

A random sample of size 20 from a normal population will sample mean 42 and sample standard deviation of 6 . To test the hypothesis the population mean 44 at 5% level of significance , find the p-value and comment

### AP Statistics

12) Which of the following statements is true? a) The sampling distribution of the difference between two proportions will always be normal. b) When comparing two population proportions, either sample proportion can be used as the unbiased estimate of the true population ...

### statistics

1.test wheter these samples represent populations that are different from the general population- sample of 10 with a mean of 44 and sample of 1 with a mean of 48. 2. The general population of individuals has a mean of 40 , a deviation of 6, and follows a normal curve. for ...

### Statistics

1. The scores of students on the ACT college entrance examination in a recent year had a normal distribution with a mean of 18.6 and a standard deviation of 5.9. A simple random sample of 60 students who took the exam is selected for study: a) What is the shape, mean(expected ...

### statistics

Given the oft-cited statistic that 66.7% of the American public is overweight or obese, you are interested in comparing college students BMI level to the general population. Assuming that the general population has a BMI of (μ) = 27.5 using α level of .05, you ...

### stats

4. Data from the 2008 General Social Survey (GSS) sample show that the mean number of children per respondent was 1.94 with a standard deviation of 1.70. A total of 2,020 people answered this question. (a) Estimate the population mean number of children per adult using a 90% ...

### stat

Find an estimate of the sample size needed to obtain the specified margin of error for the 95% confidence interval. A researcher wishes to estimate the mean amount of money spent per month on food by households in a certain neighborhood. She desires a margin of error of . Past...

### math-test statistic

If we have a sample of 12 drawn from a normal population, then we would use as our test statistic A) z0 with 11 degrees of freedom B) t0 with 12 degrees of freedom C) z0 with 12 degrees of freedom D) t0 with 11 degrees of freedom

### statistics

2. Assume that the population proportion of adults having a college degree is 0.35. A random sample of 200 adults is to be selected to test this claim. A) What is the shape, mean, and standard deviation of the sampling distribution of the sample proportion for samples of size ...

### Statistics

The mean of a population of raw scores is 33 1_X 5 122 . Use the criterion of .05 and the upper tail of the sampling distribution to test whether a sample with X 5 36.8 1N 5 302 represents this population. (a) What is the critical value? (b) Is the sample in the region of ...

### statistics

IQ scores are normally distributed with a mean of 105 and a standard deviation of 18. Assume that many samples of size n are taken form a large population of people and the mean IQ score is computed for each sample. If the sample size is n=64, find the mean and standard ...

### Statistics

A population has a mean of 200 and standard deviation of 50 and simple random sample size of 100 and x is used to estimate u. What is the probility that the sample mean will be within plus or minue 5 of the population mean?

### stats

On a test of motor coordination, the population of average bowlers has a mean score of 24, with a standard deviation of 6. A random sample of 30 bowlers at Fred's Bowling Alley has a sample mean of 26. A second random sample of 30 bowlers at Ethel's Bowling Alley has a mean of...

### Math

On a test of motor coordination, the population of average bowlers has a mean score of 24, with a standard deviation of 6. A random sample of 30 bowlers at Fred's Bowling Alley has a sample mean of 26. A second random sample of 30 bowlers at Ethel's Bowling Alley has a mean of...

### statistics

The College Board reported the following mean scores for the three parts of the Scholastic Aptitude Test (SAT) (The World Almanac, 2009): Assume that the population standard deviation on each part of the test is = 100. a. What is the probability a sample of 90 test takers will...

### statistics

The College Board reported the following mean scores for the three parts of the Scholastic Aptitude Test (SAT) (The World Almanac, 2009): Assume that the population standard deviation on each part of the test is = 100. a. What is the probability a sample of 90 test takers will...

### Statistics

The College Board reported the following mean scores for the three parts of the Scholastic Aptitude Test (SAT) (The World Almanac, 2009): Assume that the population standard deviation on each part of the test is = 100. a. What is the probability a sample of 90 test takers will...

### Math

The College Board reported the following mean scores for the three parts of the Scholastic Aptitude Test (SAT) (The World Almanac, 2009): Assume that the population standard deviation on each part of the test is = 100. a. What is the probability a sample of 90 test takers will...

### statistics

Use the given information to find the minimum sample size required to estimate an unknown population mean μ. How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters? We want 99% confidence that the sample mean is within 4 ...

### MATH STATS

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### statistics

An important indicator of lung function is forced expiratory volume(FEV), which is the volume of air that a person can expire in one second. Dr. Jones plans to measure FEv in a random sample of n young women from a certain population, and to use the sample mean as an estimate ...

### Statistics

Trying to finish an assignment: What happens to the power of the z test when the standard deviation increases? and Is the shape of a sampling distribution always the same as that of the null hypothesis population? Thanks! As the SD increases, the exactness of the estimate of a...

### 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 of 120 items. Provide a 95% confidence ...

### 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 95% confidence interval for m. Explain the ...

### statistics

Suppose a random sample of 36 is selected from a population with a standard deviation of 12. If the sample mean is 98, the 99% confidence interval to estimate the population mean is

### Statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: A. a sample of 10 with a mean of 44. B.a sample of 1 with a mean of 48. The general population of ...

### statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### Statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### psy325

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### Statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### Statistics

: For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### statistics

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...

### statistics

Random samples of size n are selected from a normal population whose standard deviation is know to be 2. Suppose you want 90% of the area under the sampling distribution of x bar to lie within + or - 1 unit of a population mean u. Find the minimum sample size n that satisfies ...

### statistics

Which of the following criteria must be met to do a one-sample test for a proportion? A. The data values in the sample must be independent. B. The parent population must be normally distributed. C. The data must come from a random sample. D. The sample size must be more than ...

### MTH- STAT 201

Can someone please help how to solve this I keep getting the wrong answer so I am now freaking out and clueless 23) The following data show the average retirement ages for a random sample of workers in Boscov’s and a random sample of workers in ShopRite. Boscov’s: Sample ...

### statistics

Determine the sample size required to estimate a population proportion to within 0.032 with 95.7% confidence, assuming that you have no knowledge of the approximate value of the sample proportion. Sample Size = B. Repeat part the previous problem, but now with the knowledge ...

### Math

I need help with this these two problem PLEASE!!! For a population with a mean of μ 80 and a standard deviation of 12, find the z-score corresponding to each of the following samples. a. M 83 for a sample of n 4 scores b. M 83 for a sample of n 16 scores c. ...

### Statistics (39)

Suppose a random sample of size 40 is selected from a population with = 9. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate). a. The population size is infinite (to 2 decimals). b. The ...

### Economics (39)

Suppose a random sample of size 40 is selected from a population with = 9. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate). a. The population size is infinite (to 2 decimals). b. The ...

### statistics

a. A random sample of 25 was drawn from a normal distribution with a standard deviation of 5. The sample mean is 80. Determine the 95% confidence interval estimate of the population mean.

### Statistics

he Oil Price Information Center reports the mean price per gallon of regular gasoline is $ 3.79 with a population standard deviation of $ 0.18. Assume a random sample of 40 gasoline stations is selected and their mean cost for regular gasoline is computed. 1. What is the ...

### statistics

Suppose a random sample of size 50 is selected from a population with σ = 10. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate). a. The population size is infinite (to 2 decimals). ...

### statistics

Suppose a random sample of size 50 is selected from a population with σ = 10. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate). a. The population size is infinite (to 2 decimals). ...

### Statistics

True or false: as then number in the sample becomes larger and larger (assuming it means as the sample gets larger and larger), then the mean of the sampling distribution is equal to the population distribution for any normal population. Is it false? That it would be ...

### Math

True or false: as then number in the sample becomes larger and larger (assuming it means as the sample gets larger and larger), then the mean of the sampling distribution is equal to the population distribution for any normal population. Is it false? That it would be ...

### Statistics

Suppose that a sample of size 60 is drawn from a population with mean 73 and standard deviation 79. Find the value of , the standard deviation of the distribution of sample means. How do I work this on my calculator?

### math

sample of 40 observations is selected from one population with a population standard deviation of 4.6. The sample mean is 101.0. A sample of 47 observations is selected from a second population with a population standard deviation of 4.0. The sample mean is 99.3. Conduct the ...

### statistics

Given a sample size of 38, with sample mean 660.3 and sample standard deviation 95.9 we are to perform the following hypothesis test. Null Hypothesis H0: ƒÊ = 700 Alternative Hypothesis H0: ƒÊ ‚ 700 At significance level 0.05 3. Calculate the test statistics (Tip: this...

### algebra

Three firms carry inventories that differ in size. Firm A's inventory contains 2000 items, firm B's inventory contains 5000 items, and firm C's inventory contains 10,000 items. The population standard deviation for the cost of the items in each firm's inventory is = 144. A ...

### statistics

In performing a hypothesis test, the null hypothesis is population mean = 6.9 and the alternative hypothesis is population mean ≠ 6.9, a random sample of 16 items is selected. The sample mean is 7.1 and the sample standard deviation is 2.0. The population is approximated...

### statistics

A researcher wants to carry out a hypothesis test involving the mean for a sample of n = 20. While the true value of the population standard deviation is unknown, the researcher is reasonably sure that the population is normally distributed. Given this information, which of ...

### What is the best estimate of the population mean?

The Jolliebee hamburger chain specializes in half-pound hamburgers. The sales follow a normal distribution. The standard deviation of the distribution for daily sakes is $3000. A sample of 40 showed the mean daily sale to be $20,000. What is the best estimate of the population...

### 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 obtained from a sample of 120 items. ...

### probability and statistics

a population forms a normal distribution with a mean of u=80 and a standard deviation of o=15. for each of the following samples, compute the z-score for the sample mean and determine whether the sample mean is a typical, representative value or an extreme value for a sample ...

### 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 the standard deviation is 6. Conduct a ...

### 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 the standard deviation is 6. Conduct a ...

### basic statistics for the behavioral sciences

on a standard test of motor coordination, a sports psychologist found that the population of a average bowlers had a mean scores of 24,with a standard deviation of 6. she tested a random sample of 30 bowling alley and found a sample mean of 26, a second random sample of 30 ...

### Statistics

A new manager, hired at a large warehouse, was told to reduce the 26% employee sick leave. The manager introduced a new incentive program for the company's employees with perfect attendance. The manager decides to test the new program to see if it's better and plans to use a ...

### statistics

Scores on a national writing exam are approximately normally distributed, with a mean of 490 and a standard deviation of 20. Consider random samples of size 25 from the population of test takers. describe the sampling distribution of a sample mean. shape mean= standard ...

### Stats

A random sample of 100 GMAT scores has a mean of 500. Assume that GMAT scores have a population standard deviation of 120. Construct a 95% confidence interval estimate of the mean GMAT scores. (15 pts) What is the sample size for the conference interval? What is the point ...

### statistics

for the population consisting of four abservations 1,3,5,7, find the dampling distribution of the sample mean for sample size n=2

### math

The sample mean to be calculated from a random sample of size n= 4 from a population consistsof eight measurements (2, 6, 9, 12, 25, 29, 39, 50) . find the sampling distribution of y y .(hint : there are 70 samplesof size 4 when sampling from a population of eight measurements )