two sample mean t 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, ..

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..

Select the incorrect statement. I. For a 95% confidence interval for the mean, when the sample size is 26, the value of t ∝ /2 is 2.036. II. For a 98% confidence interval for the mean, when the sample size is 19, the value o..

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..

Physical Meaning of Angular Momentum - Consider a particle capable of rotation about an axis. At any time t, let its momentum be and , the position vector. Then the angular momentum is given by the cross product and . = x..

The normal monthly precipitation (in inches) for a sample of 32 cities is shown. Estimate the mean precipitation(μ) per city with 99% confidence. => 1.92 < μ < 3.12 or 1.71 < μ < 3.22 or 2.24 < μ < 3.06 or 2.16 < μ < 3.2..

A tooth paste tube is supposed to contain 150g of toothpaste, with a standard deviation of 2g. A random sample of 53 tubes is found to have a mean weight of 148.5g. Does this sample differ significantly from the standard at 0.05 level of significance? => Yes ..

A standard notebook is supposed to have on an average, 200 pages, with a standard deviation of 2 pages. From a supply of 2500 notebooks, a random sample of 40 notebooks was taken and found that the mean number of pages in the notebook was 197. Determine the standard er..