two sample mean test

Before we perform the t test in order to test the difference between two means (independent samples) we need to perform _____ test to check the difference between ______. => F test, means or F test, variances ..

A cement manufacturer claims that the maximum final setting time of cement is 10 hours. A sample of 13 bags were tested and found that the mean of the maximum final setting time was 11.2 hours with a standard deviation of 1.8 hours. At α = 0.01, can the..

Health Care Organisations claim that on an average an insured woman stays for 2.1 days in the hospital for normal delivery where as an uninsured woman stays for 1.8 days. If two samples of 16 and 12 are considered with the variances of 0.54 and 0.65 days, find the ..

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 ..

A population consists of the five numbers 1, 3, 5, 7 and 9. Consider all the samples of size 2 that can be drawn without replacement from the population. Find the mean and the variance of the sampling distribution means. => 6 and 4.05 or 6 and 3 or ..

If two samples have means of 30 and 28 and variances of 12 and 14, with 20 and 25 as the sizes, find the z score for difference of two population means. => 2.154 or 2.075 or 2.320 or 1.857..

A central office operator has observed that the long distance telephone calls are normally distributed with a mean of 6 minutes and a standard deviation of 2 minutes. If random samples of 32 calls were selected, what is the probability that the length of the sampl..

Overview of methods of data collection: Census Sample survey Experiment Observational study Planning and conducting surveys: Characteristics of a well-designed and well-conducted survey Populations, samples, and random selection Sources of bias in s..

A food processing company must decide to accept or reject an entire shipment of potatoes based on the detailed examination of just a small number of potatoes selected at random from the shipment. The catalog states that the mean weight of a bag is 5 pounds with a standard deviation of 0.1..

In 2002 Football World Cup finals tournament a total of 64 matches were played and an average of 2.52 goals were scored per match. Assume the standard deviation to be 1.5. If a random sample of 10 games is selected, then find the probability that the mean of the s..