When testing for the difference between the means of two independent populations with equal variances and with samples of sizes n1 = 20 and n2 = 20, what is the number of degrees of freedom?
A) 40
B) 38
C) 20
D) 19
Q. 2Let X1, X2,......,Xk be a set of k continuous random variables. The function F(x1, x2, .....,xk)which defines the probability that simultaneously X1 < x1, X2 < x2 and so on is called a:
A) marginal distribution function.
B) marginal cumulative distribution function.
C) joint cumulative distribution function.
D) normal distribution function.
Q. 3If X and Y are random variables, the sum of all the conditional probabilities of X given a specific value of Y will always be:
A) the average of the possible values of X.
B) the average of the possible values of Y.
C) 1.
D) 0.
Q. 4Which of the following distributions is used when estimating the population mean from a normal population with unknown variance?
A) the t distribution with n + 1 degrees of freedom
B) the t distribution with n degrees of freedom
C) the t distribution with n - 1 degrees of freedom
D) the t distribution with 2n degrees of freedom
Q. 5The median, the second quartile, and the 50th percentile are all the same.
Indicate whether the statement is true or false
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