Proof:
If X1 and X2 are independent, then E[(X1-μ1) (X2-μ2)] = 0.
If X1 and X2 are independent,
,
by definition ...equation(i)
Now,


, since
and
are
constants and we know E(constant) = constant




Let X1 and X2 be independent random variables with means μ1 and μ2, and variances σ21 and σ22, respectively. Find the correlation of X1 and X1 + X2. Note that: The covariance of random variables X; Y is dened by Cov(X; Y ) = E[(X - E(X))(Y - E(Y ))]. The correlation of X; Y is dened by Corr(X; Y ) =Cov(X; Y ) / √ Var(X)Var(Y )
Consider the following hypothesis test. H0: μ1 − μ2 = 0 Ha: μ1 − μ2 ≠ 0 The following results are for two independent samples taken from the two populations. Sample 1 Sample 2 n1 = 80 n2 = 70 x1 = 104 x2 = 106 σ1 = 8.4 σ2 = 7.2 (a) What is the value of the test statistic? (Round your answer to two decimal places.) (b) What is the p-value? (Round your answer to four decimal places.)...
Consider the following hypothesis test. H0: μ1 − μ2 = 0 Ha: μ1 − μ2 ≠ 0 The following results are from independent samples taken from two populations. Sample 1 Sample 2 n1 = 35 n2 = 40 x1 = 13.6 x2 = 10.1 s1 = 5.9 s2 = 8.5 (a) What is the value of the test statistic? (Use x1 − x2. Round your answer to three decimal places.) (b) What is the degrees of freedom for the t...
Consider the following hypothesis test. H0: μ1 − μ2 = 0 Ha: μ1 − μ2 ≠ 0 The following results are from independent samples taken from two populations assuming the variances are unequal. Sample 1 Sample 2 n1 = 35 n2 = 40 x1 = 13.6 x2 = 10.1 s1 = 5.3 s2 = 8.3 What is the value of the test statistic? (Use x1 − x2 .(Round your answer to three decimal places.) ________________. What is the degrees of...
Let X1, ...., Xm be iid N(μ1,σ2) and Y1, ..., Yn be iid N(μ2,σ2), and X's and Y's are independent. Here -∞<μ1,μ2<∞ and 0<σ<∞ are unknown. Derive the MLE for (μ1,μ2,σ2). Is the MLE sufficient for (μ1,μ2,σ2)? Also derive the MLE for (μ1-μ2)/σ.
Considering two Gaussian distributions N1~(μ1,σ1^2) and N2~(μ2,σ2^2), we pick two random variables x1 and x2 in order to compute the sum x3=x1+x2. We want to prove that: a) x3 follows a gaussian distribution b) estimate mean value μ3 and variance σ3^2 c) repeat the above steps for multivariate Gaussian distributions N1~(μ1,Σ1) and N2~(μ2,Σ2)
Find the standardized test statistic to test the claim that μ1 ≠ μ2. Assume the two samples are random and independent. Population statistics: σ1 = 0.76 and σ2 = 0.51 Sample statistics: x1 = 3.6, n1 = 51 and x2 = 4, n2 = 38
Ho: μ1 - μ2 = 0 Ha: μ1 - μ2 ≠ 0 When testing above hypotheses the test statistic t was found to be 5.15. If the degrees of freedom = 40, then, the p-value for this test would be Question options: a) less than zero b) between 0 and 0.5 c) less than .005 d) greater than 1
Give a 95% confidence interval, for μ1−μ2μ1-μ2 given the following information. n1=45n1=45, ¯x1=2.67x¯1=2.67, s1=0.69s1=0.69 n2=20n2=20, ¯x2=2.8x¯2=2.8, s2=0.61s2=0.61 <μ1−μ2
Find the standardized test statistic to test the claim that μ1 < μ2. Two samples are random, independent, and come from populations that are normally distributed. The sample statistics are given below. Assume that σ 2 /1 = σ 2 /2 . n1 = 15 n2 = 13 x1 = 27.88 x2 = 30.43 s1 = 2.9 s2 = 2.8