In a randomized comparative experiment on the effect of color on the performance of a cognitive task, researchers randomly divided 69 subjects (31 males and 38 females ranging in age from 17 to 25 years) into three groups. Participants were asked to solve a series of 6 anagrams. One group was presented with the anagrams on a blue screen; one group saw them on a red screen; and one group had a neutral screen. The time, in seconds, taken to solve the anagrams was recorded. The paper reporting the study gives x⎯⎯⎯=11.5 and s=4.4 for the times of the n= 21 members of the neutral group.
A. Give a 95% confidence interval for the mean time in the population from which the subjects were recruited. B. What conditions for the population and the study design are required by the procedure you used?
C. Which of these conditions are important for the validity of the procedure in this case?

question:

could we have options?

the correct option is:

b. a value of the variable that makes the polynomial equal to zero.

the root or roots of a polynomial are the values of the variable that makes the polynomial equal to 0. we can find the roots of a polynomial making the expression equal to 0 and then, isolating the variable (it it has just one variable).

for example, given the following polynomial:

the root or zero of the polynomial, can be found by making the expression equal to 0, and then, isolating the variable, so, finding the root we have:

therefore, we have that the root of the polynomial is equal to 2.

we must remember that the number of roots that a polynomial can have, will depend on the degree of the polynomial, a first degree polynomial have will have one single root, a second degree polynomial (quadratic expression) may have two roots and so.

hence the correct option is:

b. a value of the variable that makes the polynomial equal to zero.

have a nice day!

what is the question?

we need to divide the number of toy dinosaurs, 156, by the number of brothers, 4:

in order to estimate, we can use compatible numbers:

156 ÷ 4

  ↓

160   ÷ 4 = 40        

the correct answer is a).