udy is conducted to find the mean life of a certain manufacturer's car batteries. A random sample of 34 batteries is selected and a mean of 47.5 months with a standard deviation of 7.3 months is found. Find a 95% confidence interval for the mean battery life. State the margin of error . Round to 2 decimal places. What value for  or  did you use in this calculation? State the confidence in

Q: In a random sample of five mobile​ devices, the mean repair cost was ​$60.00 and the standard…

A: The summary of statistics is, x¯=60,s=11,n=5 The degree of freedom is, df=n-1   =5-1   =4 Critical…

Q: A survey of 100 retailers revealed that the mean after-tax profit was $80,000. Assuming that the…

A: Given data,n=100σ=15,000x=80,000z-value at 95% confidence is Zc=1.96

Q: random sample of 1666 adults in the U.S. was asked how old they were when they had their first…

A:

Q: Use these data and a population standard deviation of 1.11 to construct a 98% confidence interval to…

A: The sample of 36 women's who had babies in the hospital during the past year is taken. The…

Q: A random sample of 54 four-year-olds attending day care centers provided a yearly tuition average of…

A:

Q: In the 2018 General Social Survey, a random sample of 1666 adults in the U.S. was asked how old they…

A:

Q: A random sample of 51 four-year-olds attending day care centers provided a yearly tuition average of…

A:

Q: The average length of machine-made candy from the newly-acquired machine was calculated using 52…

A: Given,sample size(n)=52sample  mean(x¯)=4.8population standard…

Q: Experience has shown that the weight of lemons produced by an orchard is normally distributed, with…

A:

Q: Q3.d. A sample of 150 Samsung phone batteries showed a mean lifetime of 1400 hours and a  standard…

A: For Samsung : x¯1=1400s1=120n1=150   For i-PHONE : x¯2=1200s2=80n2=200 BUT WE NEED TO CHECK WHETHER…

Q: In a hospital, a sample of 8 weeks was selected, and it was found that an average of 529 patients…

A:

Q: A random sample of 100 observations produced a mean x̅ =38.5 and a standard deviation of 3.2. find a…

A: Given information Sample size(n) = 100 Sample mean x̅ =38.5 Sample standard deviation = 3.2…

Q: The tolerable level of a certain pollutant is 16 mg/l. A researcher takes a sample of size n=50, and…

A:

Q: A random sample of 87 airline pilots had an average yearly income of $99,400 with a standard…

A: Givensample size(n)=87Mean(x)=99400standard deviation(s)=12000

Q: When preparing a national standardized test to be given to sixth graders, The Standard Test Company…

A: We have given that  Sample size n = 50 Sample mean = 135  Standard deviation = 20 95% confidence…

Q: The average length of machine-made candy from the newly-acquired machine was calculated using 52…

A: If population standard deviation σ is known, then Confidence interval (C.I) for true population mean…

Q: In a random sample of four mobile devices, the mean repair cost was $70.00 and the standard…

A: Given data,x=70s=14n=4α=0.05df=n-1=3t-critical value at α=0.05 and df=3 is tc=3.182

Q: Suppose from random sample of 500 teenagers, the mean number of sweaters owned was 12.5 and a…

A:

Q: A sample of 8 adult elephants had an average weight of x = 12300 pounds. The sample standard…

A: Given that, Mean = 12300 Standard deviation = 22 Sample size = 8

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: Find a 99% confidence interval for μ.

A: The sample size is n = 7 Sample mean = 46.14 Sample SD s = 1.19 At 99% confidence level and df = (n…

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 quality control manager at a light bulb factory needs to estimate the mean life of a large…

A:

Q: A cheese maker sells cheese in wheels that are known to have a standard deviation of 1.9ounces. If a…

A:

Q: SAT scores are normally distributed with a mean of 1,500 and a standard deviation of 300. An…

A: Given that  Population mean μ =1500 Population standard deviation =300 Margin of error =E =5

Q: A random sample of 50 airline pilots had an average yearly income of $110,000 with a standard…

A:

Q: A manager is interested in estimating the mean time (in minutes) required to complete a job. His…

A:

Q: A manufacturer produces 1000 lightbulbs an hour from a given machine. An quality control engineer…

A: Level of Significance: In testing of hypothesis, Level of Significance is the probability of…

Q: Construct a 95% confidence interval for the population mean, µ. Assume the population has a normal…

A: Here given Sample Size= 16 Sample mean= 645 hrs=X¯ Sample SD= 31 Hrs=s

Q: A random Sample of 55 students has a text score with x̄ =78.5 Assume the population standard…

A: Confidence interval give a range of values for the unknown parameter of the population. The width of…

Q: The average daily volume of a computer stock in 2011 was μ=35.1 million​ shares, according to a…

A:

Q: The average expenditure on Valentine's Day was expected to be $100.89. The average expenditure in a…

A: Obtain the 99% confidence interval for the difference between the two population means. The 99%…

Q: A small sample was taken from a large mass and the standard deviation was 0.2; the average was found…

A: We have to find out the arithmetic mean of the main mass according to 95% confidence interval...

Q: In a study it was found out of a random sample of 30 there was a sample standard deviation of 2.4.…

A:

Q: ɔ. What was the standard deviation, assuming that the population standard deviation is known? a. The…

A: Given Xbar=6.29 95℅ confidence interval

Q: A biology student measured the ear lengths of an SRS of 10 Mountain cottontail rabbits. The ear…

A: Given: Sample size n=10 Population standard deviation σ=0.4

Q: SAT scores are normally distributed with a mean of 1,500 and a standard deviation of 300. An…

A: We want to find the sample size (n)

Q: A statistician chooses 27 randomly selected đates, and when examining the occupancy records of a…

A: It is given that Sample size n = 27 Sample SD s = 5.86 The critical values of Chi-square at df = (n…

Q: A sample of 20 bags of mulch had a mean weight of 52 pounds with a standard deviation of 3.8 pounds.…

A: Given that  Sample Mean \bar XXˉ = 5050 Sample Standard Deviation (s)(s) = 3.83.8 Sample Size…

Q: A sample of 8 adult elephants had an average weight of 12,300 pounds. the standard deviation for the…

A: Confidence interval when population standard deviation is not known:The formula of confidence…

Q: The length of a doohickey is normally distributed with a standard deviation of 8 inches. If a random…

A: We want to find the 96% CI for population mean μ

Q: The standard deviation, S, for the annual medical cost of 24 households was found to equal $1689…

A: Suppose σ is the annual medical cost for all households.

Q: The purchasing manager of a certain company needs to estimate the mean life of lightbulbs. He…

A: Sample size (n) = 40 Sample mean (X¯) = 360 Standard deviation (σ) = 100 Confidence level = 99%…

Q: A random sample of 40 students has mean annual earnings of $3120 and a standard deviation of…

A:

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

A: Given : s

Q: 900 students were surveyed and had an average GPA of 2.7 with a standard deviation of 0.4. Calculate…

A:

Q: In a random sample of 25 ​people, the mean commute time to work was 31.8 minutes and the standard…

A:

Q: The director of vehicle maintenance for a large mass transportation authority wants to know the…

A: In this question, we have a sample of 100 tires and mean life of tire is 20,000 miles and standard…

Q: A large city newspaper periodically reports the mean cost of dinner for two people at restaurants in…

A: Determine the sample size n needed. Here, confidence level is 0.95. Use EXCEL Procedure for…

Q: A certain medication is known to increase the pulse rate of its users. The standard deviation of the…

A:

Estimation

A new framework of data analysis where the new statistical methods are used for interpreting the results and analyzing the data is known as estimation in statistics.