samples mean

Which of the following is a property of sampling distribution? I. Mean of sampling distribution equals population mean. II. Sample mean comes closer to population mean than any other unbiased mean. III. As sample..

What formula is used to gain information about a sample mean when the variable is normally distributed or when the sample size is 30 or more? => z = X - μ σ or z = X ‾ - μ σ n or z = X ‾ - μ σ n or z = X - μ σ..

A population consists of the five numbers 2, 4, 6, 8 and 10. Consider all the samples of size 2 that can be drawn with replacement from the population. Find the mean of the sampling distribution means. Also find the difference between the population mean..

Select the correct statement(s). I. Increase in sample size will make the confidence interval of the population mean wider. II. A 90% confidence interval will be wider than a 99% confidence interval. III. Sample mean can never be the same as population m..

If two samples have means of 24 and 28 and standard deviations of 4 and 6, with 12 and 15 as the sizes, find the z score for difference of two population means. => 2.07 or 7.73 or 1.07 or 1.93..

A mail order firm professional wishes to estimate the average time taken to deliver the packet(s). How large a sample must she select if she desires to be 90% confident that the true mean is within 3 days of sample mean? The standard deviation of the delivery..

What are the 95% and 99% confidence intervals for the population mean, if the variance is 0.64? Given that sample size = 60, sample mean = 11.21. => (11.29, 11.371) and (10.933, 11.467) or (10.997, 11.403) and (10.997, 11.403) or (11.01, 11.41) and (10.94, 11..

For a sample mean of 35.3, and a given standard deviation the 95% confidence interval for a population mean was calculated as 33.894 < μ < 36.316. Which is the correct representation after rounding the values? => 33.894 < μ < 36.316 or 33.89 < μ..

The average age of the employees in an organization is 34 years. Assume the variable is normally distributed and the standard deviation is 4. If 25 employees are selected at random, then find the probability that the sample mean age of the employees is less than 35 years. => 89...

An athlete wishes to estimate the mean number of miles run by him per day during practice session. The number of miles run by him on 7 days selected randomly is 7.2, 7, 7.5, 7.8, 7.6, 8 and 7.5. Based on the sample mean, what is the point estimate of the mean..