sample mean

Assume that the weights of 3,000 students at a university are normally distributed with mean 150 pounds and a standard deviation of 2.72 pounds. How many samples would you expect to find the mean below 146 pounds? => 7 or 6 or 5 or 8..

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 or z test, means or z test, variances..

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 error. => 6...

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? => 150 lbs, 7 10 ..

The manager of a company wishes to estimate the average age of the present employees. From the past records, the standard deviation is found to be 8 years. A sample of 100 employees are selected and the mean is found to be 42.8 years. Find the 99% confidence interval of the popu..

The mean life span of an electric bulb is 350 hours, with a standard deviation of 10 hours. A random sample 40 of a particular brand of electric bulbs is taken and found that their mean life span was 348 hours. State the null hypothesis( H o ) for the situation. => H o..

Which of the statement(s) are not true about degrees of freedom? I. The term "degrees of freedom" is used to describe the number of values in the final calculation of a statistic that are free to vary. II. The degrees of freedom decrease when we have to estimate more parameters. III. The degrees of..

A retail garment shop receives a shipment of trousers, with a standard length of 49.0 in. and a standard deviation of 1.0 inch. A random sample of 32 trousers had a mean length of 48.8 in. Find the standard error. => 5.0 or 3.2 or 1.0 or 0.18..

An unfair coin has a 60% chance of landing heads-up. If X = 1 represents a coin landing heads-up, and X = 0 represents a coin landing tails-up, then find the sampling distribution of the mean( x ‾ ) for samples of size 3. => Figure 4 or Figure 2 or Figure 1 or ..

A study of 50 basket ball players showed that their scoring average is 15.8 points per game. The 90% confidence interval of the mean score for all players is between 14.1 and 17.5. Find the 90% confidence interval of the mean score(μ) if 100 players are considered instead of ..