The yearbook committee polled 80 randomly selected students from a class of 320 ninth graders to see if they would be willing to
pay more for a yearbook if their names were printed on the front. Of the students who were surveyed, 26 of them said they would be willing to pay extra. With a desired confidence interval of 90%, which has a z*-score of 1.645, what is the margin of error of this survey? E = z* 4% 6% 8% 9%
Find the sample size and sample proportion then multiply the sample proportion by 1-p divide the result by n take the square root of the calculated value multiply the result by the appropriate z value.
Sample size = 80 sample proportion is the number in the sample with the characteristic of interest, divided by n, so it is computed by = 26/80 = .325 or .33 The margin of error for this polling question is calculated in this matter: Z* square root of ((p(1-p)) divided by sample size=1.645* square root of (.33)(.67) divided by 80= 1.645 * 0.0526= 0.0865 or 8.7% According to this data, you conclude with 90% confidence that 33% of the students who were surveyed are willing to pay extra have a margin of error of 8.7% which rounds out to 9%
You know when it is a periodic function if the values repeats in regular intervals or periods. An example of this is trigonometric functions that repeat over intervals of 2 pi radians.
To find the slope of the graph you pick any piece of the line, and divide the vertical difference between its ends by the horizontal difference between its ends. If the graph is distance versus time then the slope represents the speed.