Four students were discussing how to find the unit rate for a proportional relationship. Which method is valid? O "Look at the graph of the relationship. Find the y-value of the point that corresponds to x= 1. That value is the unit rate."
O "Look at the graph of the relationship Count the number of units up and the number of units to the right one must move to
arrive at the next point on the graph. Write these two numbers as a fraction."
O "Look at the graph of the relationship. Find the x-value of the point that corresponds to y = 2. That value is the unit rate."
O "Look at the graph of the relationship. Find two points which have y-values that are one unit apart. The unit rate is the
difference in the corresponding x-values."

The survey of study habits and attitudes (ssha) is a psychological test that measures the motivation, attitude toward school, and study habits of students, scores range from 0 to 200. the mean score for u.s. college students is about 115, and the standard deviation is about 30. a teacher who suspects that older students have better attitudes toward school gives the ssha to 55 students who are at least 30 years of age. the mean score is 113.2. assume the population standard deviation is 30 for older students what is the margin of error for a 95% confidence interval for the population mean score for a. older students? b. compute the 95% confidence interval for the population mean score for older students. c. compute the 99% confidence interval for the population mean score for older students. d. compute the 88% confidence interval for the population mean score for older students.