mean deviation

Standard Deviation - of a statistical data is defined as the positive square root of the arithmetic mean of the squared deviations of items from their arithmetic mean of the series under consideration. The standard deviation is denoted by s (sigma)...

A management firm wants to estimate the mean cost of repairing the apartments that are vacated by tenants. A sample of 18 vacated apartments resulted in a mean repair cost of $109 with a standard deviation of $12. Find the 90% confidence interval to estimate the m..

To qualify in a competitive examination, candidates must score in the top 5% in the examination. The test has a mean of 200 and a standard deviation of 20. What is the lowest possible score to qualify? Assume the test scores are normally distributed. => 202.6 or 200 or 232.9 or ..

As the sample size n increases without limit, the shape of the distribution of the sample means taken with replacement from a population with mean μ and standard deviation σ will approach a normal distribution. This distribution will have mean μ a..

A truck was loaded with sacks of onions whose weights were normally distributed with a mean of 35 lb and a standard deviation of 2 lb. What is the probability that a sack of onions will weigh more than 37 lb? => 0.1857 or 0.3143 or 0.1587 or 0.3413..

To qualify as a contestant in a swimming event, a swimmer has to be in the top 20% of all entrants. The swimming times are normally distributed, with a mean of 70 min and a standard deviation of 3 min. What is the qualifying time for the event to the nearest minute? => 66.4 min ..

Suppose the number of games in which major league baseball players play during their careers is normally distributed with mean equal to 1,500 and standard deviation equal to 350 games. What percentage play in fewer than 750 games? => 98.39% or 1.62% or 48.39% or 51.62%..

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 between 147 and 155 pounds? => 83 or 82 or 84 or 81..

In a factory manufacturing umbrellas, it was found that 90% of packages (containing 100 umbrellas each) did not have any defective umbrellas, 5% contained 1 defective unit each and 3% contained 2 defective units each and 2% contained 3 defective units. Find the mean, variance and standard..

A magazine report stated that the average business traveler will spend $180 per week on calls. A sample of 20 business travelers are selected at random and their mean expenses was found as $185 with a standard deviation $15. Is there enough evidence to reject the report at &alph..