Answer:
15
Step-by-step explanation:
2/3 of 30 is 20, so 1/2 of 30 is 15
All circles are similar because all circle have same shape.
However Two circles are congruent , if and only if their radii are congruent.
In our question we are asked when are all circles similar given if their radii are congruent.
So we can say this statement is false because no matter the radii are congruent or not , two or more circles are always similar because of their same shape no matter what the measure of their radii is. Only if we are asked when they are congruent, we will consider the radii part.
Answer is false.
Answer: 0.84
Step-by-step explanation:
let p be the population proportion of adults who smoked a cigarette in the past week.
As per given , we have

Sample size : n= 1491
The sample proportion of adults smoked a cigarette= 
The test statistic for proportion is given by :-

Substitute all the values , we get

Hence, the value of the test statistic = 0.84