standard deviation

The scores made by candidates in a certain test are normally distributed with mean of 500 and standard deviation of 100. What percentage of candidates received scores between 400 and 700? => 88.15% or 81.85% or 88.51% or 85.81%..

In an aptitude test conducted to qualify for a job, the scores given were normally distributed with a mean of 75 and a standard deviation 8. If only top 15% were to be selected, then find the cut - off scores. => 83.8 or 88.3 or 83.3 or 85..

A machine produces bolts, of which 10% are defective. Find the probability that in a random sample of 400 bolts produced by the machine, between 35 and 45 will be defective. Assume a standard deviation of 6. => 0.5640 or 0.6405 or 0.4605 or 0.4560..

The average price of a bicycle is $300. The prices of the bicycles are normally distributed with a standard deviation of $60. What is the probability that a randomly selected bicycle costs more than $450? => 0.62% or 6.2% or 3.8% or 0.38%..

The number of stamps of different countries collected by Edward are 96, 98, 98, 105, 36, 87, 95 and 93. Find the mean and the standard deviation. => 416.25, 20.4 or 88.5, 20.4 or 20.4, 5.77 or 20.4, 4.51..

In a report, the standard deviation of the weights of male student athletes is stated as 2 pounds. The standard deviation of weight of a random sample of 24 male student athletes was found as 1.9 pounds. Find the chi-square test value. At α = 0.01 is th..

The mean score on a standardized test is 100 with a standard deviation of 8. A random sample of 48 scores was found to have a mean of 98. Test at the 0.05 level of confidence and state whether or not to accept the null hypothesis. => The null hypothesis is accepted or ..

Which of the following statement(s) is/are false? I. The coefficient of nondetermination is found by subtracting the coefficient of determination from 1. II. As the correlation coefficient approaches zero, the coefficient of determination increases more rapidly. III. The standard error of..

In a survey conducted, 4 out of every 7 people play computer games. If 147 people are selected at random, then find the standard deviation of the number of people playing computer games. => 36 or 63 or 6 or 84..

Which of the following controls the spread of normal curve? I. standard deviation II. mean III. median IV. mode => III and IV only or II only or III only or I only..