variance over mean

= np (p+q) n - 1 ..

Let X be a discrete random variable which can assume values x 1 , x 2 , x 3 ,x n with probabilities p 1 , p 2 , p 3 .. p n respectively then (a) Mean of X or expectation of X denoted by E(X) or m is given by (b) Variance of X denoted by s 2 is given ..

The mean for the number of viewers of a sample of entertainment programs is 132, with a variance of 23. The mean for the number of advertisements of a sample of entertainment programs is 182, with a variance of 62. Compare the variations. => The number of vie..

A population consists of the five numbers 1, 3, 5, 7 and 9. Consider all the samples of size 2 that can be drawn without replacement from the population. Find the mean and the variance of the sampling distribution means. => 6 and 4.05 or 6 and 3 or 5 and 3.05 or 5 and ..

In a school, 40% of the students play basketball. If 400 students are selected at random, then find the mean and variance of the number of students who play basketball. => 160, 9.8 or 96, 160 or 96, 9.8 or 160, 96..

10% of students in a school are left-handed. If 350 students are selected at random, then find the mean, variance, and standard deviation of the number of students who are left-handed. => 40, 36, 6 or 5.61, 31.5, 35 or 35, 31.5, 5.61 or 31.5, 35, 5.61..

A survey found that 54% of the people believed that Andy Roddick would win this year's US Open. If 250 people are selected at random, then find the mean and variance of the number of people who believe that Andy Roddick would win this year's US open. => 135, 7.88 or 135, 62.1 or..

The means of each group of a two-way analysis of variance for two independent variables are plotted and shown in the three graphs. Which of these represents a disordinal interaction? Consider the interaction to be significant. => Both graph 1 and graph 2 or Graph 1 or Graph 3 or..

What are the 95% and 99% confidence intervals for the population mean, if the variance is 0.64? Given that sample size = 60, sample mean = 11.21. => (11.29, 11.371) and (10.933, 11.467) or (10.997, 11.403) and (10.997, 11.403) or (11.01, 11.41) and (10.94, 11.48) or (1..

If two samples have means of 30 and 28 and variances of 12 and 14, with 20 and 25 as the sizes, find the z score for difference of two population means. => 2.154 or 2.075 or 2.320 or 1.857..