The dot plots show the number of hours a lightbulb lasts from two different brands. Which of the following statements is correct?

a. the mean for brand a is the same we the mean for brand b

b. there were more lightbulbs in the dot plot for brand a than in the dot plot for brand b

c. the mean for brand b is higher than the mean for brand a

d. the mean for brand a is higher than the mean for brand b

C. The mean for brand B is higher than brand A.

Step-by-step explanation:

What we're looking for is the true statement of these 4.

We already know B is out, because there were 11 lightbulbs on brand B, and 10 on brand A.

Because of that, A is also out, because the means cannot be the same.

As a result, only C and D remain.

Now, add the 10 dots on brand A.

((1000 * 1) + (1100 * 2) + (1200 * 3) + (1300 * 4))/10

(1000 + 2200 + 3600 + 5200)/10

(3200 + 3600 + 5200)/10

(6800 + 5200)/10

12000/10

Brand A has an average of 1200 hours/lightbulb

Then, add the 11 on brand B

((1400 * 1) + (1500 * 4) + (1600 * 2) + (1700 * 1) + (1800 * 1) + (1900 * 1))/11

(1400 + 6000 + 3200 + 1700 + 1800 + 1900)/11

(7400 + 3200 + 1700 + 1800 + 1900)/11

(10600 + 1700 + 1800 + 1900)/11

(12300 + 1800 + 1900)/11

(14100 + 1900)/11

16000/11

Brand B has an average of 1454 hours 27 minutes 16 seconds 364 milliseconds/lightbulb

Comparing the two averages, we come to the realization that D is out because Brand A's average was less than Brand B's.

That leaves C as our answer.

step-by-step explanation:

proofs involving isosceles triangles often require special consideration because an isosceles triangle has several distinct properties that do not apply to normal triangles.(more about triangle types) therefore, when you are trying to prove that two triangles are congruent, and one or both triangles, are isosceles you have a few theorems that you can use to make your life easier.

step-by-step explanation:

an isosceles triangle has two congruent sides and two congruent angles. the congruent angles are called the base angles and the other angle is known as the vertex angle. ∠bac and ∠bca are the base angles of the triangle picture on the left. the vertex angle is ∠abc