Sunday

April 20, 2014

April 20, 2014

Number of results: 71,320

**statistics**

Refer to Table 1 in the article Snail Shells in a Practical Application of Statistical Procedures in the Electronic Reserve Readings. Find the margin of error, E, with a confidence interval of your choosing (50-99%). What is the significance of choosing a confidence interval...
*Thursday, April 26, 2012 at 3:37pm by len*

**statistics**

95% confidence interval indicates that you have 5% outside the confidence interval and 2.5% on either side. This is an area of .025. You can use a calculator or a t-table to find the critical value. Multiply that value times the standard deviation. add this value to the mean ...
*Wednesday, February 13, 2013 at 1:08pm by JJ*

**Statistics**

The standard deviation for a population is σ = 15.3. A sample of 36 observations selected from this population gave a mean equal to 74.8. a) Make a 90% confidence interval for μ b) Construct a 95% confidence interval for μ. c) Determine a 99% confidence interval...
*Thursday, November 21, 2013 at 11:11am by ----*

**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 interval is successful or not, but 95% of ...
*Friday, May 18, 2012 at 5:02pm by Mary*

**Statistics**

We have calculated a 95% confidence interval for a proportion and would prefer the confidence interval to be more precise, that is narrower. Using the same sample, we can narrow the confidence interval using which of the following? A) increasing the confidence level B) ...
*Sunday, October 27, 2013 at 9:07am by Nick*

**Statistics**

A confidence interval was used to estimate the proportion of statistics students that are females. A random sample of 72 statistics students generated the following 90% confidence Interval: (.43, .63). based on the interval above, is the population proportion of females equal ...
*Monday, November 22, 2010 at 11:41pm by Anonymous*

**statistics**

What do confidence intervals represent? What is the most controllable method of increasing the precision of or narrowing the confidence interval? What percentage of times will the mean, or population proportion, not be found within the confidence interval?
*Friday, April 30, 2010 at 7:04pm by Amy*

**Statistics**

The 95% confidence interval is: (a) Larger than the 99% confidence interval (b) Smaller than the 99% confidence interval (c) The same as the 99% confidence interval
*Sunday, October 28, 2007 at 8:18am by Thano*

**Statistics**

Multiple Choice Which of the following statements is true about the 95% confidence interval of the average of a sample? A) 95 of 100 avgs of samples will be within the limits of the confidence interval. B) There is a 95% chance the avg of the population to be within the limits...
*Friday, July 26, 2013 at 6:00am by Andrew*

**Statistics**

1. A certain population follows a normal distribution, with mean m and standard deviation s = 2.5. You collect data and test the hypotheses H0: m = 1, Ha: m 1. You obtain a P-value of 0.022. Which of the following is true? Why? a. A 95% confidence interval for m will include ...
*Saturday, November 29, 2008 at 8:32am by Latoya*

**Statistics**

. As the sample size increases The confidence interval also increases (gets larger) The confidence interval decreases (gets smaller) The confidence interval stays the same The population mean increases.
*Tuesday, June 22, 2010 at 10:54am by Jacob*

**Statistics **

Answer the question Yes or No. Sam computed a 90% confidence interval for from a specific random sample of size n. He claims that at the 90% confident level, his confidence interval does not contain . Is this claim correct? Answer a. No b. Yes
*Saturday, July 7, 2012 at 3:52pm by Desperate *

**Statistics**

A random sample of 90 observations produced a mean that = 25.9 and a standard deviation s =2.4 (a)Find a 95% confidence interval for u (b)Find a 90% confidence interval for u (c)Find a 99% confidence interval for u (Use integers or decimals for any number in the expression. ...
*Sunday, March 23, 2014 at 9:30am by Carol Harper*

**Statistics:Significance Test and Confidence Interv**

Significance Test and Confidence Intervals In General: The article contains a 95% confidence interval. Would the margin of error in a 99% confidence interval computed from the same data be less, the same, or greater?
*Tuesday, September 11, 2007 at 4:30pm by Carma*

**statistics**

Use a proportional confidence interval formula: CI95 = p + or - (1.96)(0.015) ...where p = x/n Note: + or - 1.96 represents 95% confidence interval. For p in your problem: 40/400 = .1 I let you take it from here to calculate the interval.
*Friday, May 18, 2012 at 10:19pm by MathGuru*

**Statistics**

90% confidence interval indicates that 90% of the confidence intervals that you form using the same procedure will contain the true mean of the population. You had a sample and you are trying to predict the mean response from the total population. That is why we create a ...
*Wednesday, March 13, 2013 at 4:42pm by Dr. Jane*

**statistics**

Use confidence interval formulas to construct the interval for µ. CI95 = mean + or - 1.96 (sd/√n) ...where + or - 1.96 represents the 95% interval using a z-distribution, sd = standard deviation, and n = sample size. Confidence interval using a t-distribution would be ...
*Thursday, October 15, 2009 at 10:15am by MathGuru*

**Statistics**

In 1998 a San Diego Reproductive clinic reported 49 live births to 207 women under the age of 40 who had previously been unable to get pregnant. Using the 90% confidence interval calculated above, would it be misleading for the clinic to report a success rate of 25%? A) Yes, ...
*Sunday, October 27, 2013 at 9:15pm by Jeffrey*

**Statistics**

Use a confidence interval formula for proportions. Here's one example: CI99 = p + or - (2.58)(sqrt of pq/n) ...where sqrt = square root, p = x/n, q = 1 - p, and n = sample size. Remember you need a 90% confidence interval; my example uses a 99% confidence interval. You will ...
*Monday, July 8, 2013 at 11:39am by MathGuru*

**statistics**

Consider a 90% confidence interval for μ. Assume σ is not known. For which sample size n=10 or n=20, is the confidence interval longer?
*Monday, October 31, 2011 at 2:51pm by Morgan*

**Statistics: Two Sample Population Confidence Inter**

All of the confidence interval qustions can be answered by reading the Wikepieda article cited in the last question above.
*Tuesday, September 11, 2007 at 4:28pm by DrBob222*

**statistics**

Is it inside or outside your 90% confidence interval? With that interval, what would be your degree of confidence?
*Saturday, November 5, 2011 at 10:35pm by PsyDAG*

**statistics**

P(proportion) is 0.05446, n is 863 and a 90% confidence interval is required. What is this confidence interval?
*Friday, December 23, 2011 at 11:43am by blue*

**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 ...
*Saturday, April 27, 2013 at 6:54pm by Steph*

**statistics**

Use a confidence interval formula: CI90 = mean ± 1.645(sd/√n) ...where ± 1.645 represents the 90% confidence interval using a z-table, sd = standard deviation, √ = square root, and n = sample size. Plug your data into the formula to calculate the confidence ...
*Monday, June 18, 2012 at 3:02pm by MathGuru*

**Math/Statistics**

The smaller the confidence interval, the more accurate your estimate is. One way to decrease your confidence interval is to use a larger sample. "Too wide" is a judgement call.
*Tuesday, October 2, 2012 at 10:07am by PsyDAG*

**Statistics/Confidence Intervals**

A t-distribution is sensitive to the size of the sample when considering confidence intervals. If a z-distribution is used instead of a t-distribution with small sample sizes, the confidence interval may be too narrow and the ability to estimate the true population mean may be...
*Saturday, June 21, 2008 at 2:34pm by MathGuru*

**statistics**

Use a confidence interval formula: CI90 = mean ± 1.645(sd/√n) ...where ± 1.645 represents the 90% confidence interval using a z-table, sd = standard deviation, √ = square root, and n = sample size. Plug your data into the formula to calculate the confidence ...
*Wednesday, June 13, 2012 at 8:38pm by MathGuru*

**Math Statistics**

5. Students in an introductory statistics class were asked to report the age of their mothers when they were born. Summary statistics include Sample size: 36 students Sample mean: 29.643 years Sample standard deviation: 4.564 years a. Calculate the standard error of this ...
*Monday, July 29, 2013 at 1:15pm by James*

**statistics**

Use a proportional confidence interval formula: CI95 = p + or - (1.96)(√pq/n) Note: + or - 1.96 represents 95% confidence interval. For p in your problem: .42 For q: 1 - p = 1 - .42 = .58 n = 1500 I let you take it from here to calculate the interval.
*Monday, March 25, 2013 at 10:46pm by MathGuru*

**Elementary Statistics**

1) Construct a confidence interval of the population proportion at the given level of confidence. x=60,n=300, 99% confidence. The 99% confidence interval is (_,_) 2) A researcher wishes to estimate the proportion of adults who have high-speed internet access. What size sample ...
*Wednesday, June 6, 2012 at 10:22pm by Erin*

**Statistics**

Use the sample data and confidence level to construct the confidence interval estimate of the population p....n=5200, x=4821, 99% confidence
*Wednesday, May 1, 2013 at 9:51pm by Tangee *

**statistics**

Find the 98% confidence interval using a z-table. Find the formula for the confidence interval using standard deviation. Remember that standard deviation is the square root of the variance. Substitute what you know into the formula from the information given to determine the ...
*Wednesday, August 12, 2009 at 10:37pm by MathGuru*

**statistics**

10. Using the results of a Newsweek poll conducted in March of 2009, a 90% confidence interval on the proportion of adult Americans who have a favorable opinion of Barack Obama is given by (0.699, 0.741). If everything else is the same, but the confidence level increases, ...
*Wednesday, May 8, 2013 at 3:42pm by ali awan*

**statistics**

Consider a 95% confidence interval for a population mean constructed from a random sample of 250 observations taken from a Normal population. Sigma is known to be 14. If we were to construct another 95% confidence interval, this time using 1,000 observations, how would the ...
*Sunday, February 20, 2011 at 7:02pm by AMY*

**statistics**

Consider a 95% confidence interval for a population mean constructed from a random sample of 250 observations taken from a Normal population. Sigma is known to be 14. If we were to construct another 95% confidence interval, this time using 1,000 observations, how would the ...
*Sunday, February 20, 2011 at 7:02pm by AMY*

**BIOLOGY - LAB**

What is Confidence Interval? Is it better to have a large Confidence Interval or a small Confidence Interval? Briefly explain.
*Tuesday, March 24, 2009 at 12:50pm by biology*

**Statistics Question (Confidence Interval)**

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*Wednesday, March 14, 2012 at 11:15am by v*

**Statistics**

I'll give you a hint to help you make the selection: A 95% confidence interval means that there is a 95% probability that the true population proportion lies within the confidence interval.
*Friday, May 18, 2012 at 5:02pm by MathGuru*

**Statistics**

Please help!! I have no idea how to do this question. 14. A sample of 40 CDs from your collection showed a mean length of 52.74 minutes with a standard deviation of 13.21 minutes a. Construct the 95 percent confidence interval for the mean. b. Construct the 95 percent ...
*Monday, October 31, 2011 at 1:54pm by Kristi*

**statistics**

Use a proportional confidence interval formula: CI95 = p + or - (1.96)(√pq/n) Note: + or - 1.96 represents 95% confidence interval. For p in your problem: 520/1000 = .52 For q: 1 - p = 1 - .52 = .48 n = 1000 I let you take it from here to calculate the interval.
*Wednesday, May 1, 2013 at 9:54am by MathGuru*

**statistics**

Use a proportional confidence interval formula: CI95 = p + or - (1.96)(√pq/n) Note: + or - 1.96 represents 95% confidence interval. For p in your problem: 6062/12000 = 0.505 For q: 1 - p = 1 - 0.505 = 0.495 n = 12000 I let you take it from here to calculate the interval.
*Sunday, June 23, 2013 at 5:01pm by MathGuru*

**Statistics**

Should companies use the same confidence interval each time a confidence interval is determined or should the level change based on situations? If it changes based on situations, what type of situations might call for higher confidence levels?
*Friday, April 6, 2012 at 9:04pm by John*

**statistics**

Example of a proportional confidence interval formula: CI99 = p + or - (2.58)[√(pq/n)] ...where p = x/n, q = 1 - p, and n = sample size. Note: + or - 2.58 represents 99% confidence interval. For p in your problem: 7/200 = .035 For q: 1 - p = 1 - .035 = .965 n = 200 I let...
*Thursday, March 1, 2012 at 7:22pm by MathGuru*

**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 interval are met. 1) Check conditions 2) confidence...
*Thursday, April 11, 2013 at 11:41am by MELISSA *

**statistics**

Example of a proportional confidence interval formula: CI95 = p ± (1.96)[√(pq/n)] ...where p = x/n, q = 1 - p, and n = sample size. Note: ± 1.96 represents 95% confidence interval. For p in your problem: 350/757 = .46 For q: 1 - p = 1 - .46 = .54 n = 757 I let you take ...
*Wednesday, June 13, 2012 at 6:51pm by MathGuru*

**Statistics**

Example of a proportional confidence interval formula: CI99 = p + or - (2.58)[√(pq/n)] ...where p = x/n, q = 1 - p, and n = sample size. Note: + or - 2.58 represents 99% confidence interval. For p in your problem: 135/500 = 0.27 For q: 1 - p = 1 - 0.27 = 0.73 n = 500 I ...
*Monday, June 17, 2013 at 2:46pm by MathGuru*

**Statistics**

Example of a proportional confidence interval formula: CI95 = p + or - (1.96)[√(pq/n)] ...where p = x/n, q = 1 - p, and n = sample size. Note: + or - 1.96 represents 95% confidence interval. For p in your problem: 40/90 = 0.44 For q: 1 - p = 1 - 0.44 = 0.56 n = 90 I let ...
*Monday, June 17, 2013 at 2:01pm by MathGuru*

**Environmental Management**

A. The 95% confidence interval is: (a) Larger than the 99% confidence interval (b) Smaller than the 99% confidence interval (c) The same as the 99% confidence interval
*Monday, July 13, 2009 at 2:35pm by Jox*

**statistics**

The Frayed Nerves Anxiety Scale (FNAS) is used to measure the anxiety level of people on a scale from 0 to 1000. Four students were randomly chosen and given the FNAS before their second exam. Their scores were 700, 653, 740, and 707. The standard deviation sigma of the test ...
*Monday, October 17, 2011 at 7:10pm by Anand*

**Statistics**

Proportional confidence interval formula: CI90 = p ± (1.645)[√(pq/n)] ...where p = x/n, q = 1 - p, and n = sample size. Note: ± 1.645 represents 90% confidence interval. For p in your problem: 350/500 For q: 1 - p = q n = 500 I let you take it from here to calculate the ...
*Tuesday, April 30, 2013 at 12:35am by MathGuru*

**Statistics**

Proportional confidence interval formula: CI90 = p ± (1.645)[√(pq/n)] ...where p = x/n, q = 1 - p, and n = sample size. Note: ± 1.645 represents 90% confidence interval. For p in your problem: 135/420048 For q: 1 - p = q n = 420048 I let you take it from here to ...
*Tuesday, April 30, 2013 at 1:04am by MathGuru*

**statistics**

A confidence interval for the mean is a range ģlower < ģ <ģupper where the lower bound is the smallest value of ģ that we expect and the upper bound is the largest value of ģ that we expect(Doane-Seward,2007). If we wanted a narrower interval(i.e. more precision) we ...
*Friday, April 30, 2010 at 7:04pm by Natasha*

**statistics**

Help!!!!!! A confidence interval estimate for the population mean is given to be (39,90, 48.11) If the standard deviation is 11.473 and the sample size is 52 determine the maximum error of the estimate. determine the confidence level used for the given confidence interval
*Wednesday, November 9, 2011 at 5:02pm by amy*

**Statistics**

Which of the following statements correctly interprets a 95% confidence interval on a population mean? a. It is a single point estimate b. Used to quantify the certainty of the sample standard deviation c. A 99% confidence interval is narrower than the 95% confidence interval ...
*Wednesday, September 15, 2010 at 9:18am by Beata Chmielewska*

**Statistics 101**

A researcher plans to use a random sample of n= 500 families to estimate teh mean monthly family incomefor a large population. a 99% confidence interval based on the sample would be _________ than 90% confidence interval.
*Tuesday, February 25, 2014 at 6:43pm by Deedy*

**statistics**

How large a sample would be needed to form a 90% confidence interval for the mean nicotine content of a brand of cigarettes if the nicotine content has a normal distribution with sigma equal to 8.5 mg and the width of the interval (the length of the confidence interval) equal ...
*Sunday, November 17, 2013 at 12:56pm by Alex*

**Statistics**

Use confidence interval formulas: CI99 = mean ± (2.58)(sd/√n) ...where mean = 40.78; 2.58 represents 99% interval; sd = 12.6; n = 100. Calculate the interval. Use the formula again for a 90% confidence interval using the appropriate value from a z-table. Once you ...
*Wednesday, April 4, 2012 at 5:15pm by MathGuru*

**Statistics**

95% confidence interval is approximately 2 standard deviations (SDs) away from the mean in each direction (}2 SD). Do you still believe that the 95% confidence interval would be larger for a smaller SD? I hope this helps. Thanks for asking.
*Sunday, October 28, 2007 at 8:18am by PsyDAG*

**statistics**

Example of a proportional confidence interval formula: CI99 = p + or - (2.58)[√(pq/n)] ...where p = x/n, q = 1 - p, and n = sample size. Note: + or - 2.58 represents 99% confidence interval. You will need to find the z-value for the 90% interval in the problem. For p in ...
*Monday, November 5, 2007 at 3:05pm by MathGuru*

**statistics**

Use a proportional confidence interval formula: CI95 = p + or - (1.96)(√pq/n) Note: + or - 1.96 represents 95% confidence interval. For p in your problem: 442/1004 For q: 1 - p n = 1004 Be sure to convert all fractions to decimals. It's easier to work with decimals in ...
*Monday, March 25, 2013 at 10:24pm by MathGuru*

**Statistics **

When estimating a population mean μ, where the population standard deviation σ is known, we can: a. choose a larger z value, construct a wider confidence interval, and achieve a lower confidence level b. choose a smaller z value, construct a narrower confidence ...
*Wednesday, November 14, 2012 at 7:35am by Melanie *

**statistics**

A sample of n = 9 has a mean of M = 72 with SS = 162. Use the sample to make a point estimate of ģ and to construct the 90% confidence interval for ģ. (Round all answers to two decimal places ģ = ? ± ? ( ? ) The 90% confidence interval for ģ: ( ? , ? )
*Friday, November 4, 2011 at 2:39pm by Anonymous*

**statistics**

A sample of n = 9 has a mean of M = 72 with SS = 162. Use the sample to make a point estimate of ģ and to construct the 90% confidence interval for U. (Round all answers to two decimal places.) U = ? ± ? ( ?) The 90% confidence interval for U: ( ? , ? )
*Friday, November 4, 2011 at 2:42pm by Anonymous*

**Math**

What effect will an outlier have on a confidence interval that is based on a small sample size? A) The interval will be smaller than an interval without the outlier. B) The interval will be the same with or without the outlier. C) The confidence interval will be wider than an ...
*Saturday, November 28, 2009 at 10:58am by Jennifer*

**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 sample used 45 customers rather than 18 customers, ...
*Wednesday, November 6, 2013 at 7:51pm by Katelyn*

**Statistics**

If someone gives you a sample mean and a standard deviation, you can find a confidence interval. But what if someone gives you the confidence interval instead and asks you to find the sample mean? How can you do that? Here's an example: a 95% confidence interval for a mean is ...
*Tuesday, October 4, 2011 at 7:30pm by Hope*

**Math Statistics**

Students enrolled in an introductory statistics course at a university were asked to take a survey that indicated whether the student has a visual or verbal learning style. Of the 39 students who took the survey, 25 were judged to have a visual learning style and 14 were ...
*Thursday, July 25, 2013 at 1:09am by James*

**Statistics**

A confidence interval was used to estimate the proportion of statistics students that are females. A random sample of 72 statistics students generated the following 90% confidence interval: (0.438, 0.642). Based on the interval above, is the population proportion of females ...
*Monday, August 11, 2008 at 2:11pm by Student*

**Statistics**

The confidence interval below for the population variance is based on the following sample statistics: n = 25, x-bar = 31.1, and s = 4.2. 9.29 < standard deviation squared < 42.82 What is the degree of confidence?
*Sunday, July 22, 2012 at 6:52pm by Ann*

**Statistics**

Use the sample data and confidence level to construct the confidence interval estimate of the population proportion p. n=500, x=350, 90% confidence ?<p<? (Round to three decimal places as needed.)
*Tuesday, April 30, 2013 at 12:35am by Rob*

**Statistics**

You are given the following information obtained from a random sample of 6 observations. Assume the population has a normal distribution. 13 14 17 14 17 15 a. What is the point estimate of µ? b. Construct an 80% confidence interval for µ. c. Construct a 98% confidence interval...
*Tuesday, November 12, 2013 at 2:44pm by Katie*

**Statistics:Z and T Statistics: Confidence Interva**

Z and T Statistics: Confidence Intervals and Significance Tests: A friend who hears that you are taking a statistics course asks for help with a specific chemistry lab report. She has made four independent measurements of the specific gravity of a compound. The results are : 4...
*Tuesday, September 11, 2007 at 4:26pm by Carma*

**Statistics**

How would I find the confidence level (in %) if I am given the standard deviation, size of the random sample, and confidence interval?
*Wednesday, April 3, 2013 at 10:51am by C*

**statistics**

a companys ceo wanted to estimate the percentage of defective product per shipment. in a sample contianing 600 products he found 45 defective product. a. find 99% confidence interval for the true porporton of defective product show calcultions and explain process used to ...
*Tuesday, August 23, 2011 at 7:06pm by crystal*

**statistics**

A school psychologist is trying to determine the lower boundary of a confidence interval for a IQ measure that has a mean of 100 and a standard deviation of 30 and a sample size of 100. What is the lower boundary if she was to create a 95% confidence interval?
*Friday, July 1, 2011 at 5:22pm by Haywood*

**Statistics**

The point estimate is an estimate of the population percentage given the sample you are working with. Percentage = 96/240 = p-hat q-hat = 1 - p-hat 97% confidence interval means that you have 3% left which is split between two tails. You need to split .03 in half to get .015. ...
*Sunday, March 10, 2013 at 5:12pm by Dr. Jane*

**statistics**

A 90% confidence interval for a population mean based on 144 observations is computed to be (2.7,3.4). How many observations must be made so that 90% confidence interval will specify the mean to within ± 0.2
*Thursday, October 6, 2011 at 2:08pm by Prakash*

**Statistics**

Find a confidence interval formula using proportions. Convert your proportions to decimals for ease in calculation. Use + or - 1.96 for the interval in the formula to represent 95 percent confidence (this is found using a z-table). You should be able to draw your conclusions ...
*Monday, August 31, 2009 at 6:59pm by MathGuru*

**statistics**

When a (1 - )100% confidence interval is formed for , what is the probability that the interval will not contain within its limits?
*Tuesday, November 18, 2008 at 3:04pm by Kennon*

**Statistics**

b. yes a confidence interval has the meaning that a % likelihood exists the population mean is within the interval
*Saturday, July 7, 2012 at 3:52pm by isabel *

**statistics**

Find the critical value zc necessary to form a confidence interval at the given level of confidence. a. 90% = 1.645 b. 85% = 1.8025
*Thursday, April 1, 2010 at 10:35pm by looking for someone to varify my work please*

**statistics**

Lorraine was in a hurry when she computed a confidence interval for μ. Because σ was not known, she used a Student's t distribution. However, she accidentally used degrees of freedom n instead of n - 1. Will her confidence interval be longer or shorter than one found...
*Saturday, February 18, 2012 at 1:29am by jr*

**Statistics Question (Confidence Interval)**

A sample of 15 recent college graduates found that starting salaries for attorneys in New York City had a mean of $102,342 and a standard deviation of $21,756. Construct a 95% confidence interval for the average starting salary of all attorneys in the city. A. (89869.82, ...
*Wednesday, March 14, 2012 at 11:15am by Mark*

**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 statistician calculated the 95% confidence ...
*Sunday, November 10, 2013 at 6:32pm by Katie*

**statistics**

CI95 = mean + or - 1.96(sd divided by √n) ...where + or - 1.96 represents the 95% confidence interval using a z-table, sd = standard deviation, √ = square root, and n = sample size. For the 99% confidence interval, you will have to substitute the value from a z-...
*Wednesday, September 30, 2009 at 8:37pm by MathGuru*

**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, s. Assume that all assumptions and conditions ...
*Monday, June 18, 2012 at 10:54pm by Mike*

**statistics**

A confidence interval or significance test is called stable if the confidence level or P-value does not change very much when the conditions for use of the procedure are violated
*Wednesday, April 6, 2011 at 3:38am by A confidence interval or significance test is call*

**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.
*Monday, August 23, 2010 at 6:18pm by Zodra*

**Math-Statistics**

Find a confidence interval for Ź assuming that each sample is from a normal population. a. P x = 14, Š = 4, n = 5, 90 percent confidence b. P x = 37, Š = 5, n = 15, 99 percent confidence c. P x = 121, Š = 15, n = 25, 95 percent confidence Need to show my work/formula ...
*Tuesday, December 6, 2011 at 3:48pm by Richard*

**statistics**

Pleas HeLp!!!!!!!!!! A random sample of the test scores of 100 applicants for college entry at a large junior college showed a mean score of 72.6. Determine a 99%, 95%, and 90% confidence interval for the m mean score of all applicants at the junior college. Assume the ...
*Saturday, September 17, 2011 at 10:00pm by courntey*

**Statistics**

If a 90%, 95% and 99% confidence interval are found for a population mean, how are the three interval estimates related to each other?
*Sunday, December 7, 2008 at 7:26pm by Cecilia*

**statistics**

you are constructing a 95% confidence interval using the information: n = 50, xbar = 54.3, s = 2.1 and E = 0.65. What is the value of the middle of the interval?
*Wednesday, August 12, 2009 at 10:37pm by jack*

**Statistics**

A city ballot includes a local initiative that would legalize gambling. The issue is hotly contested, and two groups decide to conduct polls to predict the outcome. The local newspaper finds that 53% of 1200 randomly selected voters plan to vote "yes," while a college ...
*Sunday, October 27, 2013 at 9:20pm by Jeffrey*

**Statistics**

Since you are already given the values for the confidence interval, take those values, add them together and divide by 2. This will be the proportion of the sample used to generate the interval. A 90% interval means that you can be 90% sure that the population proportion is ...
*Monday, August 11, 2008 at 2:11pm by MathGuru*

**Statistics-Confidence Interval**

Can someone please help me on how to work this out?? I'm so super confused. Thanks! A professor at Kaplan University claims that the average age of all Kaplan students is 36 years old. Use a 95% confidence interval to test the professor's claim. Is the professor's claim ...
*Monday, January 16, 2012 at 7:33pm by Sara*

**statistics**

A data set includes body temperatures of healthy adult humans for which x= 98.2 and s=0.64 F. Complete parts a) and b) below a) what is the best point estimate of the mean body temperature of all healthy humans? The best point estimate is F. b) Using the sample statistics, ...
*Tuesday, November 19, 2013 at 5:34am by anonymous*

**Statistics**

A scientist in Smallville tested the cholesterol of a random sample of 35 town residents. He constructed the following confidence interval: t-interval for μ: with 99.00% Confidence: 188 < μ(Cholesterol) < 206 What is the margin of error? A) 18 B) 9 C) 1.09 D) ...
*Wednesday, November 6, 2013 at 7:49pm by Katelyn*

**Statistics**

The standard error of the mean (SEM) is the standard deviation divided by the square root of the sample size - which in this instance is 9 - so the SEM here is 16/sqrt(9)=5.33. The question actually contains a little clue that you're probably on the right track in that very ...
*Saturday, September 13, 2008 at 5:09pm by David Q*

**statistics**

Confidence Intervals; In a survey of 1004 individuals, 442 felt that Randolph spent too much time away. Find a 95% confidence interval for the true population proportion
*Monday, March 25, 2013 at 10:24pm by ann*

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