The quantity is called the pooled variance estimate of the common variance of two unknown but equal population variances. it is the weighted average of the two sample variances, where the weights represent the: sample variances. sample standard deviations. degrees of freedom for each sample. none of these choices.

sample variances

Step-by-step explanation:

The pooled variance method is used to estimate the variance of several different population with different means, but are assume to have the same variance.

The weights represent the sample variances.

So the correct answer is

sample variances

solution:

we have to construct

∠m nt ≅ ∠p qr

the steps to draw this construction are

step 1: use a compass to draw an arc from point q which intersects the side pq at point a and the side qr at point b.

step 2: draw a segment nt and use the same width of the compass to draw an arc from point n which intersects the segment nt at a point x.

step 3:

step 4: join points n and y using a straightedge.

step 3:

option (d).maintaining the same width of the compass as ab, draw an arc from point x such that it intersects the arc drawn from n in a point y.

to draw   congruent angles , 1. width of compasses while drawing two angles should be same i.e from point at which angle has to be drawn, 2.the distance between the two points where the compass intersects the two sides should be same while drawing any two congruent angles.