College students annual earnings are normally distributed with standard deviation σ-$800. If the mean earning for...
to. Cóllege students annual earnings are hormally distributed with standard deviation σ $800. If the mean earning for group ofAstudents is $4000, construct a 95% confidence interval estimate of the mean annual earnings for all colløge students.
The monthly earnings of a group of business students are normally distributed with a standard deviation of 528 dollars. A researcher wants to estimate the mean monthly earnings of all business students. Find the sample size needed to have a confidence level of 95% and a margin of error of 126 dollars.
A sample of 31 students in normally distributed with a mean age of 22.6 years and a standard deviation of 1.6 years. Construct a 95% confidence interval for the population standard deviation of student ages. Round the boundaries to two decimal places.
The annual earnings of 12 randomly selected computer software engineers have a sample standard deviation of $ 3626 Assume the sample is from a normally distributed population. Construct a confidence interval for the population variance sigma squared σ2 and the population standard deviation sigma σ. Use a 95% level of confidence. Interpret the results. What is the confidence interval for the population variance sigma squared σ2? What is the confidence interval for the population standard deviation sigma σ? Please show...
64 college students took a placement test. Their mean score was 29.5 points with a standard deviation of 7.3 points. Construct a 95% confidence interval for the mean score on this placement exam for all students.
Suppose that the monthly return of stock A is approximately normally distributed with mean µ and standard deviation σ, where µ and σ are two unknown parameters. We want to learn more about the population mean µ, so we collect the monthly returns of stock A in nine randomly selected months. The returns are given (in percentage) as follows: 0.3, 1.3, 1.5, −0.6, −0.2, 0.8, 0.8, 0.9, −1.2 Answer the following questions about the confidence intervals for µ. (a) Construct...
A college admissions director wishes to estimate the mean age of all students currently enrolled. In a random sample of 16 students, the mean age is found to be 21.8 years. From past studies, the ages of enrolled students are normally distributed with a standard deviation of 10.1 years. Construct a 90% confidence interval for the mean age of all students currently enrolled. 1. The critical value: 2. The standard deviation of the sample mean: 3. The margin of error:...
A college admissions director wishes to estimate the mean age of all students currently enrolled. In a random sample of 24 students, the mean age is found to be 23.1 years. From past studies, the ages of enrolled students are normally distributed with a standard deviation of 10.6 years. Construct a 90% confidence interval for the mean age of all students currently enrolled. 1. The critical value: 2. The standard deviation of the sample mean: 3. The margin of error:...
A college admissions director wishes to estimate the mean age of all students currently enrolled. In a random sample of 16 students, the mean age is found to be 21.8 years. From past studies, the ages of enrolled students are normally distributed with a standard deviation of 10.1 years. Construct a 90% confidence interval for the mean age of all students currently enrolled. 1. The critical value: 2. The standard deviation of the sample mean: 3. The margin of error
A sample of 31 students in normally distributed with a mean age of 22.6 years and a standard deviation of 1.6 years. What is the right Chi-square score that would be used to construct a 95% confidence interval for the population standard deviation? Round your answer to two decimal places.