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Confidence intervals
Page 4
Questions (715)
Five independent samples, each of size n, are to be drawn from a normal distribution where sigma is known. For each sample, the
2 answers
asked by
Bill
920 views
A psychologist wants to estimate the variance of employee test scores. A random
sample of 18 scores had a sample standard
3 answers
asked by
Janelle
1,224 views
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%
3 answers
asked by
Don't get it!! :(
1,065 views
A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is 15.
a) Compute the 95 %
4 answers
asked by
TIMBERLY
2,749 views
find the 90% confidence interval for the variance and standard deviation of the ages of seniors at Oak Park College if a sample
4 answers
asked by
Diandra
2,935 views
Suppose a certain species bird has an average weight ofx=3.55 grams. Based on previous studies, we can assume that the weights
2 answers
asked by
Jacob
644 views
The Internal Revenue Service is studying contributions to charity. The mean calculated from a random sample of 36 returns is
4 answers
asked by
Joshua
1,158 views
A consumer magazine has contacted a simple random sample of 33 owners of a certain model of automobile and asked each owner how
3 answers
asked by
Tammy
797 views
A random sample of 10 observations has been drawn from a normal population, and the sample variance is found to be s² = 19.5.
4 answers
asked by
Laura
1,018 views
An assembly process includes a torque wrench device that automatically tightens compressor housing bolts; the device has a known
2 answers
asked by
Samantta
664 views
For one of the tasks in a manufacturing process, the mean time for task completion has historically been 35.0 minutes, with a
3 answers
asked by
Maliza
545 views
the following data values are a simple random sample form a population that is normally distributed, with ²= 25.0:
2 answers
asked by
Josephine
664 views
NEED HELP WITH THESE TWO
1. Find the critical values x2l and x2r that correspond to a 95% confidence level and a sample size of
5 answers
asked by
plob
1,093 views
A pizza shop owner wishes to find the 95% confidence interval of the true mean cost of a large cheese pizza. How large should
2 answers
asked anonymously
52 views
n a random sample 500 people eating lunch at a cafeteria on various Fridays, it was found that 160 preferred seafood. Find 99%
2 answers
asked anonymously
49 views
Fifty two of a test panel of 175 consumers say that they would buy cereal A if it is presented on the market and 35 of another
2 answers
asked anonymously
40 views
Suppose we have a random sample of 300 people. 30 of these people are left handed. The upper limit of the 95% confidence
2 answers
asked anonymously
45 views
In a random sample of 100 residents from a certain area it follows that 35 were in favour of the construction of a nuclear power
2 answers
asked anonymously
44 views
A random sample of 100 males shows that 31 males have a certain minor blood disorder, while a random sample of 100 females shows
2 answers
asked anonymously
50 views
Fifty two of a test panel of 175 consumers say that they would buy cereal A if it is presented on the market and 35 of another
2 answers
asked anonymously
48 views
A clothing store analyzed the value of purchases made on credit card by a sample of 30 credit card customers. The sample mean
2 answers
asked anonymously
63 views
The masses of 6 containers of Chow dog food are:
9.8 10.4 9.8 10 10.2 9.6 Find a 95% confidence interval for the mean mass of all
2 answers
asked anonymously
27 views
A recent survey of 236 customers who frequently visit convenient stores in Kimberly found that the mean value of purchases was R
2 answers
asked anonymously
52 views
A random sample of 8 cigarettes of a certain brand has an average nicotine content of 2.6 milligram and standard deviation of
2 answers
asked anonymously
52 views
The heights of a random sample of 50 Hereford calves at birth showed a mean of 71 cm and a standard deviation of 6.7 cm.
2 answers
asked anonymously
45 views
Light bulbs supplied by a certain company have a length life that is approximately normally distributed, with the standard
2 answers
asked anonymously
48 views
machine produces components, which have a standard deviation of 1.6 cm in length. A random sample of 64 parts is selected from
2 answers
asked anonymously
199 views
confidence interval
1 answer
asked by
Evodius ndibalema
48 views
.The following regression equation for quantity supplied was estimated
using a sample of fiftyobservations. Q= 2.2 + 0.104P.
1 answer
asked by
Evaristi Paulo
84 views
[uni level stats] confidence intervals and stats
So if I have 158 samples, 21 positive, 126 negative and 11 invalid. I have no
1 answer
asked by
Matt
100 views
I solved following question, but I'm not sure whether I've taken the right approach Any help is highly appreciated!
Question: An
1 answer
asked by
Ashley
149 views
Constructing a Confidence Interval for a Population Mean
1 answer
asked by
Wendy Gonzalez
255 views
You measure 34 watermelons' weights, and find they have a mean weight of 74 ounces. Assume the population standard deviation is
1 answer
asked by
Wendy Gonzalez
274 views
You measure 49 dogs' weights, and find they have a mean weight of 30 ounces. Assume the population standard deviation is 12.2
1 answer
asked by
Wendy Gonzalez
177 views
Kim wants to determine a 99 percent confidence interval for the true proportion p of high school students in the area who attend
1 answer
asked by
Ace
273 views
You are sampling from a population with a known standard deviation of 20 and want to construct a 95%
confidence interval for the
2 answers
asked by
L
1,193 views
In a survey, 21 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped
1 answer
asked by
Anonymous
373 views
Can anyone help me develop 90% confidence intervals including lower and upper limits for each of the follwing data:
the
1 answer
asked by
Maya
423 views
A 95% confidence interval for a difference in proportions p1-p2 if the samples have n1=70 with p^1=0.64 and n2=90 with p^2=0.58,
2 answers
asked by
Anonymous
527 views
An athletic apparel manufacturer randomly selects 200 high school varsity basketball players. A mean height of 6.18 feet is
5 answers
asked anonymously
32 views
What is a confidence level? What is the confidence interval? Write a sentence that could appear in a research report that would
1 answer
asked by
Faye
439 views
A study based on a sample of size 25 reported a mean of 94 with a margin of error of 15 for 95% confidence
(a) Give the 95%
1 answer
asked by
YOMO
645 views
You want to rent an unfurnished one-bedroom apartment in Dallas next year. The mean monthly rent for a random sample of 11
3 answers
asked by
YOMO
957 views
The Pew Research Center Internet Project, conducted on the 25th anniversary of the Internet, involved a survey of 857 Internet
3 answers
asked by
Brandon
2,331 views
The human resources department of a consulting firm gives a standard creativity test to a randomly selected group of new hires
3 answers
asked by
Dane
1,813 views
A study was done on skull sizes of humans during different time periods. The results are shown in the table. Assume that the two
2 answers
asked by
Anonymous
1,429 views
You chose a simple random sample of 300 guests you develop a 95 percent confidence interval estimate you found the following 325
1 answer
asked by
Kim
453 views
Visitor Numbers
Total visitors: 2004. 2005. 2006 3,135,727. 3,164,906. 3,281,435 Total visitor days: 2004. 2005. 2006 7,453,465.
2 answers
asked by
Candice
477 views
The average weight of a medium size egg is found to be 3.2 oz, with a standard deviation of 0.13 oz. What is the heaviest egg
2 answers
asked by
matt
1,210 views
Question 1 Production Rates
A manufacturing company wishes to estimate the number of items that its workforce can produce on
1 answer
asked by
Lau
509 views
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Parent Categories (55)
Biostatistics
Data Analysis
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