15. If a1 and a2 are the sum and product of roots of the quadratic equation 2(x+2)²+ c(x+1)=0, where c is a constant. Show that a1 +a2 = 0

The mean of a set of data is -3.82 and its standard deviation is 2.31. find the z score for a value of 3.99.

Ms. sutton recorded the word counts and scores of the top ten essays in a timed writing contest. the table shows her data. how does the word count of an essay relate to its score in the contest? word count tends to decrease as the score decreases. word count tends to increase as the score decreases. word count tends to remain constant as the score decreases. word count has no apparent relationship to the score of the essay.

Suppose sat writing scores are normally distributed with a mean of 497 and a standard deviation of 109. a university plans to award scholarships to students whose scores are in the top 2%. what is the minimum score required for the scholarship? round your answer to the nearest whole number, if necessary.