standard deviation and variance formula

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 b..

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). The standard deviatio..

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..

If 20% of the computer chips are defective, then find the variance and standard deviation of a lot of 542 chips. => 86.72, 9.31 or 433.6, 108.4 or 108.4, 86.72 or 9.31, 86.72..

A random sample of 81 students was tested for the problem solving approach skills. The variance of the scores obtained from the sample was found to be 144. Find the 80% confidence interval for the variance and standard deviation. Assume that the variable is n..

55% of the students passed in an online examination. If 600 students are selected at random, then find the variance and standard deviation of the number of students passing the examination. => 148.5, 12.19 or 330, 12.19 or 330, 148.5 or 12.19, 148.5..

The university authorities wanted to estimate the average age of the students in their university by taking a random sample of 25 students. The standard deviation was found to be 3 years. Find the 95% confidence interval for the variance (σ 2 ) and standardh..

The shoe sizes of 10 students in a class are 4, 3, 5, 6, 3, 6, 5, 4, 3, 6. Find the variance ad standard deviation of the data. σ => Variance = 1.45; Standard deviation = 1.1 or Variance = 1.45; Standard devi..

The standard deviation of the scores of 20 students in statistics test is 10 and that of calculus test is 5. Find the F-test value and verify whether the variances for both the tests differ at 90% confidence level. => 2.16, do not differ or 2.54, do not differ or 4, di..

The average number of computer sales over a 2-month period is 86, with a variance of 36. The average of the commissions is $4,444 with a standard deviation of $888. Find the coefficient of variations of the two and state which is more variable. => 6.3%, 14.8%, commissi..