Find the value of ta/2 and n = 25 for the 90% confidence interval for the mean if the population standard deviation, ơ, is not known.

Q: an exam score has a mean of 506 and a standard deviation of 100. What exam score corresponds to a…

A: μ  = 506 , σ = 100  Z~ N(0,1)

Q: A random sample of 121 bottles of cologne showed an average content of 4 ounces. It is known that…

A: Solution-: Given:  In this problem, which type of quantity does the 4 ounces refer to?

Q: uppose that the resting h stributed with mean 80 a /hat heart rate would a m

A: Let X be a random variable with mean 80 and s.d. 15 that follows a normal distribution. So,…

Q: The heights of 8 Japanese men were taken with sample mean of 155 cm (centimeters) and standard…

A:

Q: The results of a common standardized test used in psychology research is designed so that the…

A: Suppose that the random variable x defines the scores in psychology research.

Q: Assume that adults have IQ scores that are normally distributed with a mean of 100.1 and a standard…

A:

Q: If the scores on a test have a mean of 43 and standard deviation of 1.5, what is z score of 45?

A: In order to solve for the equivalent z score, we will use the z score formulaFormula:z =…

Q: The scores on a standardized test are normally distributed with a mean of 120 and standard deviation…

A: From the provided information, Mean (µ) = 120 Standard deviation (σ) = 10 The test score is 2.1…

Q: A recent study of 28 city residents showed that the mean of the number of years they lived at their…

A: The formula of confidence interval for the population mean is given by                  confidence…

Q: The scores on a psychology test were normally distributed with a mean of 65 and a standard deviation…

A: According to empirical rule 68%,95% and 99.7% data fall within one ,two and three standard…

Q: The scores on a standardized test are normally distributed with a mean of 95 and standard deviation…

A:

Q: Assume that adults have IQ scores that are normally distributed with a mean of 95.6 and a standard…

A: Given: x~N(μ,σ)μ=95.6σ=24.3

Q: What is the z-score for this raw score?

A:

Q: The scores on a standardized test are normally distributed with a mean of 80 and standard deviation…

A:

Q: Assume that adults have IQ scores that are normally distributed with a mean of 103.1 and a standard…

A: According to the given information in this questionWe need to find first quartile

Q: Assume that adults have iq scores that are normally distributed with a mean of 97.9 and a standard…

A:

Q: In a population, the data value 180 has a z score of -0.8. The standard deviation of this population…

A: The question is about z score.Given :Raw value ( x ) = 180z score = -0.8Standard deviation of the…

Q: What value of  zα/2  is used in the 90% confidence interval of a normal distribution?

A: It is given that, the confidence level is 0.90.

Q: The time it takes students to finish the Statistics Exam is known to be normally distributed with a…

A:

Q: The newest model of a car battery from a popular brand is supposed to have a lifetime of  60…

A: (a) To find the confidence interval for the population standard deviation, we first find the…

Q: on an exam, Tom scores 12 points above the mean and has a z-score of z=+2.00. the standard deviation…

A: It is given that the difference between mean and raw score is 12 and the z score is 2.

Q: The scores on a standardized test normally distributed with a mean of 110 and standard deviation of…

A: Here we need to find the score corresponding to  z = 2.2 standard deviations above the mean. Mean is…