standard distributions

To calculate the confidence interval for variance or standard deviation, a statistical distribution called ______ is needed. => chi-square distribution or binomial distribution or poisson distribution or multinomial distribution..

The probability distribution for the number of clients visiting a bookshop daily is presented as under. Find the mean and the standard deviation of the distribution. What is the expected number of clients visiting the bookshop? => mean = 67.66, standard devia..

What percentage of area (approximately) under the normal distribution curve lies between a standard deviation of 1 and 2? => 15% or 13% or 27% or 30%..

The average price of a computer is $750. If prices of computers are approximately normally distributed with a standard deviation of $75, then what is the probability that a randomly selected computer costs more than $1000? => 3.3% or 0.33% or 0.04% or 0.4%..

Find the highest control limit for a normally distributed curve with a mean of 20 and a standard deviation of 3. => 23 or 29 or 11 or 26..

The scores made by candidates in a certain test are normally distributed with mean 500 and standard deviation 100. What percentage of candidates received scores greater than 700? => 2.28% or 2.82% or 47.72% or 47.27%..

The scores made by candidates in a certain test are normally distributed with mean 500 and standard deviation 100. What percentage of candidates received scores which differ from 500 by more than 150 points? => 43.23% or 13.36% or 43.32% or 6.68%..

Find the probability P (0.65 < z < 1.84) using the standard normal distribution. => 22.49% or 24.29% or 29.42% or 70.93%..

Find the probability P ( z < 0.65) using the standard normal distribution. => 72.44% or 74.22% or 25.78% or 27.58%..

Find the z value so that 20% of the area under the standard normal distribution curve lies to the left of it. => - 4.772 or 4.772 or - 0.84 or 0.84..