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Confidence Interval
Page 5
Questions (364)
a. A random sample of 25 was drawn from a normal distribution with a standard deviation of 5. The sample mean is 80. Determine
3 answers
asked by
Sally
1,404 views
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
4 answers
asked by
Karen
1,376 views
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
1 answer
asked by
Kristi
1,225 views
True or false? Every random sample of the same size from a given population will produce exactly the same confidence interval
3 answers
asked by
jr
1,197 views
Salaries of 50 college graduates who took a statistics course in college have a mean, x of $68,200. Assuming a standard
2 answers
asked by
casey
1,225 views
A simple random sample of 10 households, the number of TV's that each household had is as follows:
1, 3, 1, 2, 0, 2, 1, 1, 1, 5
2 answers
asked by
Anonymous
1,220 views
A teacher wants to compare the mean geology scores of two different classes. She is testing the null hypothesis that there is no
3 answers
asked by
bobert
1,202 views
5. A random sample of size 81 has sample mean 20 and sample standard deviation 3.
(a) Is it appropriate to use a Student’s t
1 answer
asked by
Anonymous
1,208 views
Find the value of zα/2 to construct a confidence interval with level:
a. 95% b. 98%
3 answers
asked by
Ayuda!!!
1,157 views
In a sample of 200 people, 154 said they watched educational television. Find the 90% confidence interval of the true proportion
1 answer
asked by
Ale
1,146 views
A company is considering installing new machines to assemble its products. The company is considering two types of machines, but
1 answer
asked by
Jose
1,147 views
. As the sample size increases
The confidence interval also increases (gets larger) The confidence interval decreases (gets
2 answers
asked by
Jacob
1,117 views
A company has developed a new type of light bulb, and wants to estimate its mean lifetime. A simple random sample of 12 bulbs
2 answers
asked by
Sara
1,087 views
Recently, a university surveyed recent graduates of the English Department for their starting salaries. Four hundred graduates
3 answers
asked by
Ray
1,085 views
In a survey on supernatural experiences, 722 of 4005 adult Americans surveyed reported that they had seen or been with a ghost.
(
1 answer
asked by
Cara
1,071 views
The average hemoglobin reading for a sample of 20 nurses was 16 grams per 100 mL, with a sample standard deviation of 2 g.
1 answer
asked by
Anonymous
1,051 views
A test of writing ability is given to a random sample of students before and after they completed a formal writing course. The
1 answer
asked by
heather
1,033 views
The confidence interval below for the population variance is based on the following sample statistics: n = 25, x-bar = 31.1, and
3 answers
asked by
Ann
1,035 views
Hoping to lure more shoppers downtown, a city builds a new parking garage in the central business district. The city hopes that
2 answers
asked by
Katie
1,035 views
A group of 56 randomly selected students have a mean score of 30.8 and a
standard deviation of ó = 4.5 on a placement test. Find
2 answers
asked by
Erica
1,041 views
any state auto insurance company took a random sample of 370 insurance claims paid out during a 1-year period. the average claim
2 answers
asked by
b
1,056 views
Total plasma volume is important in determining the required plasma component in blood replacement theory for a person
2 answers
asked by
stan
1,012 views
Find the 99% confidence interval for the difference between two means based on this information about two samples. Assume
4 answers
asked by
Karly
1,004 views
Suppose the method of tree ring dating gave the following dates A.D. for an archaeological excavation site.
1248 1187 1199 1236
2 answers
asked by
Anonymous
1,005 views
In response to media inquiries and concerns expressed by groups opposed to violence, the president of a university with over
1 answer
asked by
Bryant
987 views
The Wall Street Journal reported that automobile crashes cost the United States $162 billion annually (The Wall Street Journal,
2 answers
asked by
SV
977 views
How much does a sleeping bag cost? Let us say you want a sleeping bag that should keep you warm in temperatures from 20ºF to
2 answers
asked by
Jared
974 views
Please only the formula and steps to do this problem. Thank you
An assembly process includes a torque wrench device that
2 answers
asked by
Lina
940 views
A savings and loan association needs information concerning the checking account balances of its local customers. A random
1 answer
asked by
Giselle
913 views
1.The average number of acts of physical violence in a random sample of 150 TV movies was 4.5 acts with a standard deviation of
2 answers
asked by
Chris
916 views
The price for 2 tickets with online service charges, large popcorn and 2 medium soft drinks at a sample of 6 theater chains:
1 answer
asked by
Anonymous
870 views
A car manufacturer is interested in conducting a study to estimate the mean stopping distance for a new type
of brakes when used
1 answer
asked by
John
896 views
A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 624 babies were born,
1 answer
asked by
Stephanie
898 views
In a sample of 200 people, 154 said they watched educational television. Find the 90% confidence interval of the true proportion
2 answers
asked by
Tessa
885 views
construct the confidence interval for the population mean c=0.98,x=5.6, s=0.6, and n=45
1 answer
asked by
Dennis
864 views
A city ballot includes a local initiative that would legalize gambling. The issue is hotly contested, and two groups decide to
1 answer
asked by
Jeffrey
867 views
A simple random sample of a size n is drawn from a population that is normally distributed. The sample mean, x is found to be
2 answers
asked by
Anonymous
884 views
Can someone guide me on how to solve this problem: A sample of 52 night students ages is obtained in order to estimate the mean
2 answers
asked by
concy
860 views
The U.S. Geological Survey compiled historical data about Old Faithful Geyser (Yellowstone National Park) from 1870 to 1987. Let
1 answer
asked by
Interval Estimate
859 views
Suppose 1,600 of 2,000 registered voters sampled said they planned to vote for the Independent candidate for president. Using
1 answer
asked by
Eric
847 views
A packing company investigates a national training consultant in hopes of improving productivity on the packing line. The
2 answers
asked by
Samantha
842 views
18 workers at a large assembly plant were asked the time it took to commute to work. The data was analyzed in Minitab and the
1 answer
asked by
Maria Elizabeth
837 views
An automotive manufacturer has selected 10 car seats to study the Rockwell hardness of the seat recliner
mechanism. A sample of 8
2 answers
asked by
t
799 views
We want a confidence interval for the mean IQ of all the 7th grade girls in that school district. We do not know the population
3 answers
asked by
moneta
587 views
A study of peach trees found that the average number of peaches per tree was 625. The standard deviation of the population is
2 answers
asked by
betsy
806 views
A random sample of 14 evenings at the O'Sullivan house hold showed that the family received an average of 2.4 solicitation calls
2 answers
asked by
Sara
801 views
We observe a sample proprotion p-hat = 0.3. If the standard deviation of the sampling distribution of p-hat is 0.04, what is the
2 answers
asked by
Morgan
793 views
In the week before and the week after a holiday, there were 12,000 total deaths, and 5916 of them occurred in the week before
1 answer
asked by
slomomo
778 views
In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be
engaged in safety and
1 answer
asked by
sam
349 views
A sample of 25 different payroll depts. found that the employees worked an average of 310.3 days a year with a standard
2 answers
asked by
Anonymous
785 views
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Parent Categories (35)
Blood Plasma Volume
Data Analysis
Data Analysis/Inferential Statistics
Descriptive Statistics
Estimation
Hypothesis Testing
Inference
Inferential Statistics
Mathematics and Statistics
Mathematics/Statistics
Maximum Likelihood Estimation
Normal Distribution
One-sample t-test
Population mean and sample mean
Population Mean and Standard Deviation
Population Proportion
Population Sampling
Probability
Probability and Statistics
Sample Mean
Sample size calculation
Sample Size Estimation
Sampling
Sampling and Estimation
Sampling and Sampling Distributions
Sampling and Surveys
Sampling Methods
Sleeping bags
Statistical Analysis
Statistical Inference
Statistical Measures
Statistics
Statistics and Probability
Survey analysis
Visitor Numbers