variance

If X is a discrete random variable then variance of X denoted by V(X) is defined as V(X) = E [X - E(X)] 2 V(X) = E(X 2 ) - [E(X)] 2 ..

We have = n(n-1) p 2 (p+q) n - 2 + np = n 2 p 2 - np 2 + np = n 2 p 2 + np(1-p) = n 2 p 2 + npq Now V(x) = E(x 2 ) - [E(x)] 2 = n 2 p 2 + npq - n 2 p 2 = n..

The formula for the confidence interval for a variance is _________ . => IV. or II. or III. or I...

What will happen to the variance and standard deviation of a data set if each numerical data is doubled? => Both would be doubled. or Variance increases by 3 times and standard deviation is doubled. or Variance is doubled and standard deviation increases by 4 times. or..

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 average score of students in statistics examination is 90, with a variance of 4. The average score of students in algebra examination is 102, with a variance of 7. Which course is more variable in terms of scores? => algebra or both are equally variable or cannot be determin..

The variance of the number of pages of a sample of 20 women's fitness magazines is 62 and the variance of the number of pages of a sample of 15 sports magazines is 23. At 90% confidence level, find the F-test value and check whether variances differ significantly. => 2..

Suppose that for the past 15 years the variance for the number of skydivers met with accident each year has been 16. Find the 90% confidence interval for the true variance. Assume that the variable is normally distributed. => between 9 and 31 or between 11 and 39 or between 10 a..

The variances corresponding to the number of students having attendence of 95% or above of a sample of 21 schools in one state and 16 schools of another are 20.3 and 9.8. Verify whether the variances for both the states differ at 80% and 90% confidence levels. => do not differ a..

The daily water usage (in gallons per person per day) of 10 families of a colony has a variance of 286. Find the 90% confidence interval for the variance and standard deviation. Assume that the variable is normally distributed. => 152 < σ 2 < 774 ; 12 < σ &l..