Question

No explanation required;
Question 1

A two-independent-sample t-test is computed when mean differences are compared between TWO OR MORE groups sampled from a population with an unknown variance.

Select one:

True

False

Q 2

Question 2

A counselor records the number of disagreements (per session) among couples during group counseling sessions. If the number of disagreements is distributed normally with a mean of 4.4 disagreements and a standard deviation of 0.4, then what proportion of couples disagree at least four times during each counseling session?

Select one:

a. .1587

b. .8413

c. The probability is not listed in the unit normal table.

d. .3413

Q 3

Question 3

For simple linear regression, the F-test for ρ2 will always produce equivalent results to the t-test for β*.

Select one:

True

False

Q 4

Question 4

Regardless of the distribution of the population, the sampling distribution of sample means will be approximately normally distributed. What characteristic of the mean explains this?

Select one:

a. Unbiased estimator

b. Minimal variance

c. Central limit theorem

d. None of these

Answer 1

Solution:

1)

True - When the population variances are Unknown, we do a 2-sample independent t-test. When the population standard deviations ARE known, we do a 2-sample z-test.

2)

P(X>= 4)

normal distribution , μ =4.4 , σ = 0.4

since this is continuous distribution, P(X>= 4) =P( X >4)

we convert this to standard normal using Z= ( X - μ) / σ

Z= (4-4 - 4 ) / 0.4

= -1.00

P(Z> -1.00) = Ares to the right of -1.00

P( X >4) =   P(Z> -1.00 ) =1 -  P(Z < -1.00 )

= 1- 0.1587

= 0.8413

3) True

4)  Option- C) central limit theorem