The results of a study indicated that the correlation between a measure of children's behavior and the number of friends they had was .80. this correlation indicates that
a. behavior and number of friends are not related.
b. behavior and number of friends are negatively related.
c. the more a child is, the more friends he or she has.

c. the more helpful a child is, the more friends he or she has.

Explanation:

The correlation coefficient between measure of children's helping behavior and the number of friends is said to be 0.80. Assuming that the significance level is already met and here we only consider correlation coefficient, a correlation coefficient of more than 0.5 is considered a strong correlation. A correlation coefficient is between 0-1 and can have a positive or negative sign. 0 represent no correlation and 1 represents maximum correlation achievable. A minus (-) or negative sign means if one decreases, the other increases. A plus (+) or positive sign means if one increases, the other also increases. Here, it is +0.8 which means the more helpful a child is, the more friends he or she has.

question - in 1827, john walker, a druggist in a small english town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. the druggist had discovered the first friction-chemical match, the kind we use to-day. it is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. although walker's match did not require the bottle of acid, nevertheless it was not a good one. it could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. in a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. the match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. it would ignite when rubbed on any dry surface, and there was no longer any sputtering. this was the phosphorus match, the match with which we are so familiar. according the paragraph what was the benefit of the new phosphorus match? it burst into flame when rubbed on sandpaper. it was made by mixing chemicals. it could be ignited on any dry surface. it threw fire in all directions.

answer - matches required natural chemicals