In hypothesis testing, if the null hypothesis has been rejected when the alternative hypothesis has been true, . a. a Type II error has been committed b. either a Type I or Type II error has been committed c. the correct decision has been made d. a Type I error has been committed

(c)

Step-by-step explanation:

Given : In a hypothesis testing the null hypothesis has been rejected when the alternative hypothesis has been true.

Find : to find that the given decision is create type I error , type II error or right decision has been taken

Step by step :

In hypothesis testing there are 2 types of error.

(1)Type I error :- if the null hypothesis is rejected when it is true, is known has Type I error .

(2)Type II error:- if the null hypothesis is accepted when alternative hypothesis is true, is known as type II error.

Since here null hypothesis has been rejected when alternative hypothesis has been true,i.e., the correct decision has been made

Hence option (c) is correct.

18

step-by-step explanation:

draw the shape and you will see that f and k are actually at adjacent vertices (points of the hexagon that are neighboring).   so find the distance between (1,2) and (4,2).   that is easy since (1,2) and (4,2) is just a vertical distance to count, which is 3.   it is a regular polygon which means all sides are congruent.   you have 6 sides (hexa) so multiply 6 by 3 to receive 18.