Answer:
the population means are known the population variances are assumed equal but unknown
Step-by-step explanation:
If σ1= σ2 (= σ) but unknown , then the biased pooled or combined estimate of the common variance σ² ( the term common variance means that each population has the same variance ) is given by
Sp²= (n1-1) s1² + (n2-1) s2²/ n1+ n2- 2
So first assumption is correct.
When the population variances are assumed unequal and unknown
If σ1 ≠ σ2 but unknown
we use the sample estimates s1 and s2 to compute the standard error of the difference between the means.
S(x1`- x2`) = √s1²/ n1 + s2²/n2
So this is does not apply here.
the answer is 8 because there is 4 sides on a square and 8 x 4 is 32.
Explanation: Probability of NOT getting a tail in 3 coin toss is (12)3=18 . Probability of getting at least 1 tail in 3 coin toss is 1−18=78
Answer:
x = -3n/4
Step-by-step explanation:
