Determine the sample size required to estimate a population mean to within 11 units given that the population standard deviation is 105. Use a confidence level of 90%. Sample Size =

Find the sample size required to estimate the mean IQ of all college students. Assume we want a 90 per cent confidence level that the sample mean is within 2 IQ points of the true population mean. Also assume that the population standard deviation is 15 IQ points.

The variance in drug weighs is critical in the pharmaceutical industry. For specific drug, with weights measured in grams, a sample of 18 units provided a sample variance =0.36.  A. Construct a 90% confidence interval estimate of the population variance for the weight of this drug.  B. Construct a 90% confidence interval estimate of the population standard deviation.  use excel please

IQ is normally distributed with a mean of 100 and a standard deviation of 16. A local school is considering what its minimum IQ score should be for admission. What should the minimum IQ score be so that 90% of all students in the area can qualify for admission? How can I calculate this using Excel or by hand

Suppose the mean height in inches of all 9th grade students at one high school is estimated. The population standard deviation is 5 inches. The heights of 8 randomly selected students are 63, 60, 74, 68, 60, 66, 72 and 61. x¯ = Margin of error at 99% confidence level = 99% confidence interval =

We wish to estimate an average number of education years for a college student atWVC. We take a sample of 47 students and find that the mean is 5.3 years and standard deviation is 0.9years.Find the 95% confidence interval for the population mean.

In a randoms sample of six people, the mean driving distance to work was 19.7 miles and the standard deviation was 6.1 miles. Assume the population is normally distributed and use the t-distribution to find the margin of error and construct a 90% confidence interval for the population mean u. Interpret the results.

The average height of students at a university from an SRS of 14 students gave a standard deviation of 2.5 feet. Construct a 95% confidence interval for the standard deviation of the height of students at the university. Assume normality for the data.

suppose a random sample of 25 observation from a normal population with standard deviation 6. Also the sample mean is 20. Find 90% confidence interval for the population mean.

Assum a sample is used to estimate a populatation mean.  Find the 95% confidence interval for a sample size of 41 with a mean of 64.2 and a standard deviation of 13.4.  Enter answer as an open interval (i.e. parentheses) accurate to 3 decimal places.