Posner, Snyder, and Davidson (1980)examined spatial attention using arrows as primes. In most of the trials the arrow pointed to the area where the stimulus would appear a moment later, but 20% of the time it did not. They compared reaction times (RTs)for trials when the cue correctly pointed to the stimulus location, for trials when the arrow pointed toward an incorrect position, and for trials with a neutral cue (no arrow).

Which of the following statements was NOT supported by their findings?

A)RTs were slower when the arrow pointed toward an incorrect location.

B)Spatial attention is limited in capacity.

C)We can attend to two different locations without a reduction in performance.

D)RTs were faster for responses for arrows pointing correctly compared to the neutral condition.

answer: the rock sample is a sedimentary rock.

explanation:

it is given that:

mass of rock sample, m = 2.7 g

volume of rock sample,

so, density of rock sample will be

since, the density of rock sample is . hence, the rock sample is a sedimentary rock, whose densities varies between .

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.