A certain brand of batteries has a lifetime that has a normal distribution with a mean of 50 hours and a standard deviation of 7 hours. What proportion of these batteries will last for more than 57 hours? You are told that P (Z < 1) = 0.84

Q: For the majority of maths tests taken at a school, it is shown that the test score is approximaly…

A: The normal distribution is the most useful theoretical distribution for continuous variable.  For…

Q: a normal distribution has a mean of 60 with a standard deviation of 8. for this population, which is…

A: Solution

Q: What z-score would be associated with the value x = 124?

A: Given that Mean = 133 SD = 6 And the value is X = 124

Q: What z-score would be associated with the value x = 143?

A: Given that Mean = 137 SD = 15 And the value X = 143

Q: If a set of data is normally distributed with a mean of 50 and a standard deviation of 5, a z-score…

A:

Q: A population of normally distributed data has a mean of 200 and a standard deviation of 20. Assuming…

A:

Q: If grades on a certain test are approximately normally distributed with a mean of 75 and a standard…

A:

Q: For a population with a standard deviation of 40, how large a sample is necessary to have a standard…

A: We want to find the sample size

Q: Given a distribution with a mean of 60 and standard deviation of 21, find a value with a z-score of…

A: Introduction:Consider X as a normally distributed random variable, with mean μ and standard…

Q: Assuming that the scores of Grade 11 students in Statistics and Probability in their third quarter…

A:

Q: If grades on a certain test are approximately normally distributed with a mean of 75 and a standard…

A: The random variable X is defined as the grades on a certain test follows normal distribution with a…

Q: The lifetime of a 2-volt non-rechargeable battery in constant use has a Normal distribution, with a…

A: Given: μ=516σ=20 The proportion of batteries with lifetimes exceeding 520 hours is obtained as…

Q: A set of test papers is normally distributed with a standard deviation of 5. If Riley scored an 83…

A:

Q: At a local high school, GPA's are normally distributed with a mean of 2.9 and standard deviation of…

A: Given problem Given that   At a local high school, GPA's are normally distributed with a mean of…

Q: The lengths of pregnancies in a small rural village are normally distributed with a mean of 261 days…

A: From the given Information, Let X represent the length of pregnancies in a small rural village and…

Q: Given a normally distributed data set whose mean is 35 and whose standard deviation is 6.3, what…

A: The random variable X follows normal distribution. The population mean is 35. The population…

Q: . Given a distribution with a mean of 60 and standard deviation of 21, find a value with a z-score…

A:

Q: A random sample of 26 psychology graduates scored an average of 458 on the GRE advanced psychology…

A: From the provided information, Sample size (n) = 26 Sample mean (x̅) = 458 Sample standard deviation…

Q: On a planet far far away from Earth, IQ of the ruling species is normally distributed with a mean of…

A: Solution: Let X be the IQ of an individual. From the given information, X follows normal…

Q: On a recent quiz, the class mean was 76 with a stanbard deviation of 3.1. Calculate the z score (to…

A:

Q: In a population with a mean of µ = 30 and a standard deviation of σ = 5, a score of X = 18 would be…

A: Given that  μ=30 , σ=5 , X=18

Q: According to a recent report, people smile an average of u=62 times per day. Assuming that the…

A: Let "X" be the average number of times that people smile in a day.

Q: In a certain factory of rags, the time it takes for the workers to finish one rag is normally…

A: Solution: Let X be the time it takes for the workers to finish one rag. From the given information,…

Q: In a certain​ study, women's heights are found to be approximately normally distributed with a mean…

A: Given that, In a certain​ study, women's heights are found to be approximately normally distributed…

Q: deviation

A: Let X = IQ of an individual. IQ of the ruling species is normally distributed with a mean of 118 and…

Q: A population has a mean of 50 and a standard deviation of 20. Would a score of x=70 be considered an…

A: The mean and standard deviation are 50 and 20.

Q: The monthly income from a particular occupation is normally distributed, with a mean of 3800 dollars…

A: Given,mean(μ)=3800standard deviation(σ)=500

Q: Given a distribution with a mean of 70 and a standard deviation of 62, find a value with a z-score…

A:

Q: For a large metropolitan area, carbon monoxide concentrations in air samples come from a normal…

A: We have to find out answer of given question....

Q: A score that is 6 points below the mean corresponds to a z-score of z = -1.50. What is the…

A: We have to find population standard deviation from given information. We need to use z score…

Q: A normal distribution has a mean of 54, and a sttandard deviation of 6. What is the probability of…

A:

Q: The numbers of books checked out daily at a local library are normally distributed with a mean of…

A:

Q: The lengths of pregnancies in a small rural village are normally distributed with a mean of 262 days…

A: Let X be the lengths of pregnancies in a small rural village x¯=262sd=16 X~ Normal (262, 162)   For…

Q: Suppose a normal distribution has a mean of 50 and a standard deviation of 3. What is P(xs 53)?

A:

Q: If a population has a standard deviation σ , then the standard deviation of the mean of 100 randomly…

A:

Q: The lifetime of a 2‑volt non‑rechargeable battery in constant use has a Normal distribution, with a…

A:

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

A: Solution-: Given: μ=263 days, σ=13 days We want to find what range would you expect to find the…

Q: For a population with mean of 50 and a standard deviation of 8, what is the Z-score that corresponds…

A: Given:  population mean of random variable x is =50 and standard deviations=8  then find z score…

Q: A set of data items is normally distributed with a mean of 40 and a standard deviation of 8. Convert…

A: Given:  Random variable x follow normal distribution with mean mu=40 ,sd=8  Then z score:…

Q: Suppose Stock A has had a mean price of $6.58 per share with a standard deviation of $1.88, and…

A: GivenFor stock A:-Mean(μ)=6.58standard deviation(σ)=1.88For Stock B:-Mean(μ)=10.57standard…

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

A:

Q: When samples of size 30 are collected from a normal population that has a mean of 200 and a standard…

A:

Q: The manufacturer of an extended-life lightbulb claims the bulb has an average life of 13,000 hours…

A: Given Information: Mean Life (u) = 13000 hours Standard Deviation (s) = 1000 hours

Q: An analyst found that the average amount of money in bank accounts at his/her bank is $2,000 with a…

A:

Q: The amount of time a certain brand of light bulb lasts is normally distributed with a mean of 1800…

A: X is normally distributed.  Mean = 1800 hours Sigma = 25 hours  X represents the amount of  time a…

Q: According to a recent report, people smile an average of u=62 times per day. Assuming that the…

A: Let "X" be people smile in a day.

Q: When Wyatt commutes to work, the amount of time it takes him to arrive is normally distributed with…

A: The arriving time to work (X) is normally distributed with mean (μ) = 45 minutes and standard…

Q: Given IQ scores are approximately normally distributed with a mean of 100 and standard deviation of…

A: From the given information,   Mean = 100 Standard deviation = 15   The objective is to find the…

Q: Suppose that the life expectancy of a certain brand of nondefective light bulbs is normally​…

A: The probability that at least 1300 ​hr is,

Q: In a certain company, every worker received a $50-per-week raise. How does this affect the mean…

A: In a certain company, every worker received a $50-per-week raise. The mean salary is the average of…

Confidence Intervals

When we calculate intervals in probability and statistics, it can be simply termed as finding out a confidence interval. The confidence interval is usually calculated from the data set which is observed. The value of the parameter that needs to be calculated is present here only.