A recent survey of 8 social networking sites has a mean of 13.1 million visitors for a specific month. The standard deviation was 4.1 million. find the 95 % confidence interval of the true mean.

Q: We notice a mean loss of 7 pounds in a sample of 11 dieters, with a standard deviation of three…

A: We first find the critical value for 95% confidence interval

Q: A pharmaceutical company claims that a drug is effective in treating 90% of people having severe…

A: Given that,The random variable follows binomial distribution,n=6p=90%=0.9,q=1-p, q= 0.1

Q: From a random sample of 64 high school seniors, the sample mean and standard deviation of the math…

A: The sample size is 64, sample mean is 96, and standard deviation is 16. The degrees of freedom is,…

Q: A significant number of students completed a Statistics exam, and the final marks had a mean of 70…

A: Answer - A significant number of students completed a Statistics exam, and the final marks had a…

Q: From a random sample of 49 high school seniors, the sample mean and standard deviation of the math…

A:

Q: If a sample has a mean of 100 and a standard deviation of 6, what is the value in the data set that…

A:

Q: If a sample has a mean of 150 and a standard deviation of 9, what is the value in the data set that…

A: Given,mean(μ)=150standard deviation(σ)=9Z-score=1.58

Q: A sample of 23 provided a sample mean of 158 and a sample standard deviation of 20. Find the value…

A: Given that Sample size n = 23 Sample mean = 158 Sample SD = 20

Q: If the average mid twenties male weighs 169lbs. and a weight of 150 is in the 31st. percentile, what…

A: We are given,Mean = μ = 169X = 150Percentile = 31st

Q: A biologist is interested in studying the effect of vitamin supplements on deer mouse body length.…

A: Note: According to Bartleby, expert solve only one question and rest can be reposted.

Q: A sample of 49 managers reveals a sample mean of $45,420. The standard deviation of the samp is…

A: As the population standard deviation is not known, we will use t-distribution. The number of degrees…

Q: The number of minutes spent reading in one day is normally distributed with a mean of μ = 23 and a…

A: The normal distribution:A continuous random variable X is said to follow normal distribution if the…

Q: A boxer would like to know the mean diameter of a navel orange. If the standard deviation is 0.3…

A: Given Standard deviations=0.3 Margin of error=0.1 At 95% confidence z=1.96

Q: According to a recent survey, the population distribution of number of years of  education for…

A: What is the standard error of mean?

Q: Suppose the scores of students on an exam are normally distributed with a mean of 276 and a standard…

A: X~N(μ= 276 , σ= 59 ) μ= 276 , σ= 59 Formula for Z-score Z=(X-μ)/σ

Q: If the height of 1000 students in a University Campus closely follows a normal distribution with a…

A:

Q: The population standard deviation for the height of college hockey players is 3.4 inches. If we want…

A:

Q: In a survey, 18 people were asked how much they spent on their child's last birthday gift. The…

A:

Q: The lengths of human pregnancies are normally distributed with a mean of 268 days, and a standard…

A: Given that, X~N(268,152) n=10

Q: Students at Arrowhead High School took a Math test with a mean of 120 and a standard deviation of…

A: Let X be the random variable of normal distribution with mean 120 and standard deviation 25 Let Z be…

Q: How large a sample should be selected to provide a 95% confidence interval with a margin of error of…

A: Given : Margin of error = 5 α = 0.05 Population standard deviation = σ = 30 zα2 = z0.052 = 1.96

Q: In a recent study of 35 Grade5 students, the mean number of hours per week that they played video…

A: We know that,  Sample size (n) = 35, sample mean (x̄) = 16.6 and population standard deviation (σ) =…

Q: A study determined the average amount a person spends on candy during Halloween is $80 with a…

A: Here, μ=80 and σ=15

Q: A study of the Physics and Astronomy department has found that 95% of the graduate students drink…

A: Explanation:Here given the two means and find out the standard deviation of the sample follows the…

Q: For a population with a standard deviation of 20, what is the zscore corresponding to a score that…

A: The population standard deviation is 20. The z-score corresponding to a score that is 5 points below…

Q: A candy store sells about 8 million pieces of candy per day with a standard deviation of 300,000…

A: Given : Let X : Number candy that they sell in a given day           μ = 8 million i.e   Mean (μ) =…

Q: The golf scores for a school team were normally distributed with a mean of 68 and a standard…

A: Let X be the golf scores. It is given that X is normally distributed with mean 68 and standard…

Q: given a standard deviation of + or - 0.023m at the 90% confidence level, what is the 68% error level…

A: The confidence level of the data is 90%. The standard deviation of the data with error percentage is…

Q: The test scores of students in a class test has a mean of 70 and with a standard deviation of 12.…

A: Given,mean(μ)=70standard deviation(σ)=12

Q: An irate student complained that the cost of textbooks was too high. He randomly surveyed 36 other…

A: Given that,x¯=121.60,σ=6.36,n=36 Critical value: By using the z-tables, the critical value at 10%…

Q: Find the margin of error for a​ 95% confidence interval for estimating the population mean when the…

A: Sample S.D = s = 110

Q: The mean score on the SAT in 2017 was 1060, and the standard deviation was 195. Assume the scores…

A: Given,  Mean μ=1060  Standard deviation σ=195Let x be score of a randomly selected person

Q: If research samples 28 college students and wants to compare the sample mean of 8 to the population…

A: From the provided information, Sample size (n) = 28 Sample mean (x̄) = 8 Population mean (µ) = 12…

Q: A Industrial Psychology test was written. From a sample of 50 students and it was found that the…

A:

Q: A company pays their employees an average of $52,500 per year. If the standard deviation for the…

A: Given : A company pays their employees an average of $52,500 per year. If the standard deviation for…

Q: A recent study found that 61 children who watched a commercial for potato chips featuring a…

A: We have to calculate the p value for the hypothesis test for the difference in the means.

Q: The heights of 18 year old men are normally distributed with a mean of 67 inches and a standard…

A: Given information- Population mean, µ = 67 inches Population standard deviation, σ = 3 inches We…

Q: How large a sample should be used to provide a 95% confidence interval with a margin of error of 4,…

A:

Q: A recent study found that 69% of all adults over 50 wear sunglasses for driving. In a random sample…

A: Formula : Mean = np Standard Deviation  :

Q: The mean height of a population of men is 70.8 inches and the standard deviation is 3.2 inches. What…

A:

Q: A study of a local high school tried to determine the mean number of text messages that each student…

A: Solution: Let X be the number of messages sent per day. From the given information, x-bar=198…

Q: The average income of a graduate from the University of Eastern West Virginia is $50,000 per year,…

A: X follows a Normal distribution with mean = 50000 and S.D = 2500 Then z=(x-mean)/SD =…

Q: Describe  the scores in a sample  that has a standard  deviation of zero

A: If the standard deviation is zero there will be no dispersion of scores from the Mean. It means that…

Q: What is the standard deviation?

A: We have to calculate the SD for the given frequency distribution.

Q: in a test of a lifelong brand of tires , a survey revealed that the mean life was 35,000 mikes and…

A: Let the random variable X be the life of tires.  The random variable X follows Normal distribution…

Q: The lengths of pregnancies in a small rural village are normally distributed with a mean of 263 days…

A:

Q: Find the 95% confidence interval for the variance and standard deviation of the heights of maple…

A: Construct the 95% confidence interval for the variance. Obtain the critical values. The standard…

Q: The standard deviation of the distribution of sample means would be equal to:

A: The standard deviation of the distribution of sample means would be equal to ?

Q: The daily sales at a convenience store have a mean of $1280 and a standard deviation of

A: As given, the daily sales at a convenience store have a mean of $1280 and a standard deviation of…

Q: A recent study of 25 motorists showed that they spent an average of P750 per week. The standard…

A: Given : s

Q: Jessica, the owner of a medium-scale native handicrafts shop, knows from experience that the time…

A:

Q: In a certain​ city, the average​ 20- to​ 29-year old man is 72.5 inches​ tall, with a standard…

A:

Q: Interpret the ­z-score of 1.45 in terms of its relationship to standard deviation as well as the…

A: Solution: From the given information, z=1.45.

Q: If the foot length of women follows a normal distribution and 95% of women have a foot length…

A: Given data: If the foot length of women follows a normal distribution 95% of women have a foot…

Q: A study of 390 kindergarten students showed that they have seen on average 4500 hours of television.…

A: Obtain the 95% confidence interval for the mean of all the students. The 95% confidence interval for…

Q: A recent newspaper article reported the results of a survey of well-educated suburban parents. The…

A: Given that 2-year-old children watching an average of 60 minutes of television each day watching an…

Q: What is the Standard Deviation?

A: You want to know about standard deviation.We will deeply understand the meaning of standard…

Q: The standard deviation of a sample is 3.0 and the standard error is -16.52, what was the original…

A: