sampling distribution for proportions

An economist wishes to estimate the average monthly rent of houses in a large city to within $25 with 99% confidence. A study of 70 houses in the city found that 49 houses had their rent as $1,000. How many houses must be surveyed in order to be justified in assuming that the sample ..

Which of the following statements is/are true? I. The sampling distribution is a theoretical distribution of a sample statistic. II. Sampling distribution is same for each sample statistic. III. A sample distributi..

Stated by French chemist Joseph Proust A chemical compound always contains same elements combined together in the same proportion by mass. For example, pure water obtained from different sources such as river, well, springs, sea, etc., always contains hydrogen and oxygen together in the ..

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 size increases, variation ..

Suppose 20% of all voters favour candidate A. Pollsters take a sample of 600 voters. Determine the probability that the sample proportion will be between 0.18 and 0.22. => 19.36% or 40.32% or 80.64% or 89.4%..

A researcher would like to estimate the proportion of all mothers who take black coffee during pregnancy. She would like to be 90% confident that the estimate is within 2.5 percentage points of the true proportion. What sample size is required? => 0.574 or 0.109 or 1,0..

Assume that the weights of 3,000 students at a university are normally distributed with mean 150 pounds and a standard deviation of 7 pounds. If 100 samples of 30 students each are obtained, then what would be the expected mean and standard deviation of the resulting sampli..

The rms speed of an oxygen molecule in a sample at 300 K is about 480m/s. This does not mean that the speed of each molecule is 480 m/s. Many of the molecules have speed less than 480m/s and many have speed more than 480m/s. Maxwell derived an equation giving the distribution..

Random Variable and Probability Distribution - If is often very important to allocate a numerical value to an outcome of a random experiment. For example consider an experiment of tossing a coin twice and note the number of heads (x) obtained. Outcome : HH HT TH TT No. of heads (x) : 2 1 ..

If is often very important to allocate a numerical value to an outcome of a random experiment. For example consider an experiment of tossing a coin twice and note the number of heads (x) obtained. Outcome : HH HT TH TT No. of heads (x) : 2 1 1 0 x is called a random variable, which can assume the v..