Roy's toys received a shipment of 100,000 rubber duckies from the factory. the factory couldn't promise that all rubber duckies are in perfect form, but they promised that the percentage of defective toys won't exceed 5\%5%. roy wanted to get an estimation of the percentage of defective toys, and since he couldn't go over the entire 100{,}000100,000 duckies, he took a random sample of 10 duckies. he found that 10% of them were defective. what type of statistical study did roy use?

Observational study

Step-by-step explanation:

There are three types of statistical study:

1) Experimental study: Under this study, an experiment is done and then the results are recorded.

2) Observational study : Under this study, events are observed and the results are recorded.

3) Survey: Under this study, a survey is carried out and the results are recorded.

Here, its not possible for Roy to check each and every toy if it is defective or not. So he took a sample and found that 10% were defective. He has carried an observational study.

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.

d) by the cross product property, ab^2 = bc multiplied by ad

step-by-step explanation:

we are given

in the given triangle abc

angle a is 90° and segment ad is perpendicular to segment bc

we can see that

triangle(abc) and triangle(abd) are similar because they have common side and same angle (90 degree)

so, triangles(abc) and abd are similar

since, they are similar

so, the ratio of their sides must be equal

we get

now, we can cross multiply

and we get

so, this could be step to prove it