# Statistics Question (Confidence Interval)

40,564 results

**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 ...

**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 ...

**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...

**Statistics**

Can anyone help me with this? Which of the following statements is true about a 99% confidence interval? a. The interval contains 99% of the population. b. The probability that the population mean is in the interval is 99%. c. The interval is wider than a 95% confidence ...

**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

**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, ...

**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

**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 ...

**Statistics**

A confidence interval for a population mean has a margin of error of 3.1. a)Determine the length of the confidence interval. b)If the sample mean is 56.7, obtain the confidence interval.

**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) ...

**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...

**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. ...

**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?

**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 ...

**Stastics**

Which of the following descriptions of confidence intervals is correct? (Select all that apply) a. If a 95% confidence interval contains 0, then the 99% confidence interval contains 0 b. If a 99% confidence interval contains 0, then the 95% confidence interval contains 0 c. If...

**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.

**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 ...

**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 ...

**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 ...

**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?

**Statistics**

Please help!! I have no idea how to do this question. 14. A sample of 40 CD’s 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 ...

**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?

**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**

An online site presented this question, 'Would the recent norovirus outbreak deter you from taking a cruise?' Among 34,327 people who responded, 66% answered 'yes'. Use the sample data to construct a 95% confidence interval estimate for the proportion of the population of all ...

**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 ...

**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 ...

**statistics**

P(proportion) is 0.05446, n is 863 and a 90% confidence interval is required. What is this confidence interval?

**Statistics**

Use the sample data and confidence level to construct the confidence interval estimate of the population p....n=5200, x=4821, 99% confidence

**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 ...

**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, what...

**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?

**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

**statistics**

The following list is a sampling of the costs of various statistics textbooks used at several colleges. Give the upper confidence limit for a 95% confidence interval estimate for the mean cost of all statistics textbooks. 109.95; 92.00; 96.70; 84.85; 92.60; 84.45; 90.95; 77.00...

**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 ...

**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

**Math-Statistics**

Find a confidence interval for ƒÊ assuming that each sample is from a normal population. a. P x = 14, ƒÐ = 4, n = 5, 90 percent confidence b. P x = 37, ƒÐ = 5, n = 15, 99 percent confidence c. P x = 121, ƒÐ = 15, n = 25, 95 percent confidence Need to show my work...

**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...

**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...

**statistics**

A sample of n = 9 has a mean of M = 72 with SS = 162. Use the sample to make a point estimate of ì and to construct the 90% confidence interval for ì. (Round all answers to two decimal places ì = ? ± ? ( ? ) The 90% confidence interval for ì: ( ? , ? )

**statistics**

A sample of n = 9 has a mean of M = 72 with SS = 162. Use the sample to make a point estimate of ì and to construct the 90% confidence interval for U. (Round all answers to two decimal places.) U = ? ± ? ( ?) The 90% confidence interval for U: ( ? , ? )

**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 ...

**BIOLOGY - LAB**

What is Confidence Interval? Is it better to have a large Confidence Interval or a small Confidence Interval? Briefly explain.

**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.)

**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, ...

**Statistics**

Express the confidence interval using the indicated format. Express the confidence interval -0.129 < p < 0.631 in the form of p ± E.

**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?

**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 ...

**Business statistics**

3. Determine the t-critical value for a two-sided confidence interval in each of the following situations. a. Confidence level = 95%, df = 15 b. Confidence level = 99%, n = 5. c. Confidence level = 95%, n = 15 d. Significance level = 0.01, df = 37

**Statistics 101**

A researcher plans to use a random sample of n= 500 families to estimate the mean monthly family incomefor a large population. a 99% confidence interval based on the sample would be _________ than 90% confidence interval.

**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, ...

**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 ...

**statistics**

Consider the data from an unknown distribution: 40.68, 32.15, 36.91, 29.00, 35.58, 41.55, 33.83, 29.07, 41.00, 37.68, 41.23, 37.54, 40.33, 36.82, 35.18, 31.67, 38.55, 38.34, 35.86, 40.45, 37.28, 36.65, 32.12, 32.96, 37.65, 39.44, 46.18, 24.21, 42.35, 33.05, 30.90, 42.12, 34.38...

**Statistics**

What is meant by the 95% confidence interval of the mean ? That 95% of my sample is OK to do more tests. That I am 95% confident that the confidence interval will contain the parameter being estimated. That 5% of my sample is not OK. That I am 95% sure that the population mean...

**statistics**

What is meant by the 95% confidence interval of the mean ? That 95% of my sample is OK to do more tests. That I am 95% confident that the confidence interval will contain the parameter being estimated. That 5% of my sample is not OK. That I am 95% sure that the population mean...

**Statistics**

Suppose you are told that a 95% confidence interval for the average price of a gallon of regular gasoline in your state is from $2.85 to $3.84. Use the fact that the confidence interval for the mean is in the form x − E to x + E to compute the sample mean and the maximal ...

**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

**MATH**

The following data represent the asking price of a simple random sample of homes for sale. Construct a 99% confidence interval with and without the outlier included. Comment on the effect the outlier has on the confidence interval. Here is the information: $231,500 $279,900 $...

**Math Stats**

The following data represent the asking price of a simple random sample of homes for sale. Construct a 99% confidence interval with and without the outlier included. Comment on the effect the outlier has on the confidence interval. Here is the information: $231,500 $279,900 $...

**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 ...

**statistics**

0.95 degree of confidence find the confidence interval for the mean of the whole population

**statistics**

Discuss the effect that the confidence level has upon the confidence interval.

**math 3**

The following data represent the asking price of a simple random sample of homes for sale. Construct a 99% confidence interval with and without the outlier included. Comment on the effect the outlier has on the confidence interval. Here is the information: $231,500 $279,900 $...

**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 ...

**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 ...

**statistics**

Using the 95% level of confidence, what is the confidence interval for the proportion of households represented at a town meeting

**statistics HELP!**

A data set includes body temperatures of healthy adult humans for which 98.1F and s= 0.56F. What is the best point estimate of the mean body temperature of all healthy humans? Using the sample statistics, construct a confidence interval estimate of the mean body temperature of...

**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) ...

**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 ...

**math please help**

The following data represent the asking price of a simple random sample of homes for sale. Construct a 99% confidence interval with and without the outlier included. Comment on the effect the outlier has on the confidence interval. Here is the information: $177,500 $279,900 $...

**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

**Statistics**

How would I find the confidence level (in %) if I am given the standard deviation, size of the random sample, and confidence interval?

**statistics**

0.95 of confidence find the confidence interval for the mean

**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 ...

**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 ...

**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, ...

**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?

**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 ...

**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 ...

**statistics**

When a (1 - )100% confidence interval is formed for , what is the probability that the interval will not contain within its limits?

**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...

**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?

**Statistics**

(25 pts, 5 pts each) The ounces of coffee that a machine dispenses in 5-ounce cups have normally distributed. Suppose a sample of size 6 was taken from this machine, as shown as follows: 5.05 5.03 5.10 5.02 4.98 5.00 (for all calculations, keep at least six decimal places) (1...

**Lab Math/Statistics**

The 95% confidence interval for a quality control specimen is 9.2-10.2 mg/dl. My question is, how do I figure out the coefficient of variation (%CV) with only this information?

**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

**statistics**

In a sample of 100 steel wires the average breaking strength is 50 kN, with a standard deviation of 2 kN. a. Find a 95% confidence interval for the mean breaking strength of this type of wire. b. An engineer claims that the mean breaking strength is between 49.7 kN and 50.3 kN...

**Statistics**

A random sample of 14 college female students revealed their average height was 66.1 inches. a) How many students should be in a samle if a 95% confidence interval is to have a margin of error of only plus/minus 1 inch? Is that the only information you were given? Were you not...

**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**

The new Twinkle bulb is being developed to last more than 1000 hours. A random sample of 100 of these new bulbs is selected from the production line. It was found that 48 lasted more than 1000 hours. Find the point estimate for the population proportion, the margin of error ...

**Business statistics**

You chose a simple random sample of 300 guests you develop a 95 percent confidence interval estimate you found the following 325 and 32 determine the standard error of the sampling distribution determine the critical value z from the standard normal table compute the ...

**math**

With a confidence level of .95 and a confident interval of 5 and a population of 20,000 what is the sample size? With a confidence level of .99 and a confident interval of 5 and a population of 20,000 what is the sample size? Finally, using the sample size for question 1 and 2...

**Statistics**

Which is true about a 99% confidence interval for a population proportion based on a given sample? I. We are 99% confident that the population proportion is in our interval. II. There is a 99% chance that our interval contains the sample proportion. III. The interval is wider ...

**Statistics**

The population standard deviation is estimated to be $300. If a 98% confidence interval is used and an interval of +/-$75 is desired, how many cardholders should be sampled?

**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 ...

**Statistics**

Sorry to ask another question but I keep struggling with this class. If all else remains the same, which of these will make a confidence interval for a proportion narrower? I. Increase the confidence level. II. Increase the sample size. III. Increase the margin of error. A. I ...

**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

**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 ...

**math statistic**

One of your friends knows that you are taking Advanced Placement Statistics and asks for your help wither Chemistry lab report. She has come up with five measurements of the melting point of a compound: 122.4, 121.8, 122.0, 123.0, and 122.3 degrees Celsius. a. The lab manual ...

**Sociology Research Methods**

What is a confidence level? What is the confidence interval? Write a sentence that could appear in a research report that would exemplify a confidence interval.

**statistics**

how do you get thesampling and confidence intervals for this problem sample scores of 1,2,3,4,5 and 95 percent confidence interval about the sample mean

**Statistics**

A survey organization takes a simple random sample of 625 households from a city of 80,000 households. On the average, there are 2.30 persons per sample household, and the SD is 1.75. Say whether each of the following statements are True or false and explain (a) The SE for the...