What is different about the normality requirement for a confidence interval estimate of the population standard deviation and the normality requirement for a confidence interval estimate of the population mean

Q: Suppose that salaries of workers in an industry are normally distributed with an unknown mean and…

A: The sample size is 48. That is, n=48 Degrees of freedom, df=n-1=48-1=47

Q: A researcher has collected the blood samples of 29 individuals and found that the mean hemoglobin…

A: Obtain the 95% confidence interval for the mean hemoglobin concentration for the population. The 95%…

Q: or False? As confidence level decreases, the required sample size increases for a fixed width of a…

A: The confidence interval can be calculated as: =x¯±z×σn Here, xˉ = Sample mean σ = Population…

Q: Salaries of 45 college graduates who took statistics course in college have a mean of 67,900…

A:

Q: Salaries of 33 college graduates who took a statistics course in college have a mean, x, of $69,000.…

A: Since we know population standard deviation, use z-distribution to find z-critical value. Find…

Q: A random sample of 12 chemists from Washington stats shows an average salary of $39,420 with a…

A: The sample mean one (Washington): x¯1=$39,420, sample mean two (New Mexico): x¯2=$30,215, population…

Q: The distribution of study times for first-year students follows a normal distribution with a…

A:

Q: In 2002, the mean age of an inmate on death row was 40.7 years with a standard deviation of 9.6…

A: Solution

Q: random sample of 20 data points has a sample mean of 375 and a sample standard deviation of 81.…

A: Given that  Sample size n =20 Sample mean=375 Sample standard deviation =81

Q: What is the difference in the computation of a confidence interval between cases in which you know…

A: Population standard deviation known: When population standard deviation is known, the z-critical…

Q: A student wants to estimate the mean score of all college students for a particular exam. First use…

A: Solution: From the given information, the possible scores range from 100 to 2200. Here, the largest…

Q: A sample of 14 commuters in Chicago showed the average of the commuting times was 33.2 minutes. If…

A: Given that x bar =33.2.s.d =8.3,n=14,alpha=.05

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: We wish to estimate an average number of education years for a college student at WVC. We take a…

A: The summary of the statistics are, The degree of freedom is, Critical value: By using the…

Q: What is the margin of error?

A: Scores on a standardized exam are known to follow a normal distribution. A researcher estimates that…

Q: Heights for teenage boys and girls were calculated. The mean height for the sample of 12 boys was…

A: The given information is that the sample size of boys is 12 with mean height is 174 cm and variance…

Q: A researcher wishes to estimate the mean cholesterol value for a certain population. Determine the…

A: Determine the sample size needed. Obtain the critical value of z at the 95% confidence level. Here,…

Q: A labor department wants to study mean age of all people in the civilian labor force. The average…

A: Given:

Q: If the confidence level is decreased and the standard deviation and sample size stay the same, then…

A: Here we need to find whether the given statement is true or false. Here it is given that the sample…

Q: Historically, the mean age of all Memphis residents has been 40 years.  You believe this has…

A: Given information Hypothesized mean µ = 40 Sample size (n) = 130 Mean x̅ = 36 Standard deviation (s)…