Are NHS Students Aware of the NHS Blog? By: Marina Lleonart, Katie McMorran and Sarah Walton
Questions • Are NHS students aware of the school blog? • Is there a difference between the proportion of underclassmen and the proportion of upperclassmen who are aware of the blog?
Design Selection Method: • List of all students in the high school. • Used a stratified random sample (dividing the students by grade) • Selected 25 students from each grade using RandInt on the calculator, ignoring repeats • Distributed survey by visiting the homerooms of selected students
Do NHS Students Use the NHS Blog? The following is a Survey being conducted for AP Statistics. Please circle your answers. Thank you for your time. Please circle your grade 9 10 11 12 Did you know that Mr. Dumais has a blog? Yes No
What is the blog? For the past two years, Mr. Dumais has maintained a school blog. The blog informs students and parents of current events as well as upcoming events.
Hypothesis TestIs there a difference in awareness of the school blog between upperclassmen and underclassmen?” UnderclassmenUpperclassmen N1: 50 N2: 50 X1: 35 X2: 32 P1: 0.7 P2: 0.64 Q1: 0.3 Q2: 0.36 H0: P1-P2 = 0 (there is no difference in awareness between upperclassmen and underclassmen) HA: P1-P2 > 0 (there is a difference in awareness between upperclassmen and underclassmen) -We will use a 1- tailed 2-proportion z-test - Alpha level: .05
Assumptions and Conditions • Independence: In reality, it is possible that a student’s awareness of the blog may be influenced by another. One grade’s overall awareness should not affect another’s, so grades are independent as well. • Random: Our subjects were randomly selected using a stratified random sample • 10% Condition: 100 students are less than 10% of the entire student population • Normal: np = (.67)(100) = 67 > 10 nq = (.33)(100) = 33 > 10
Conclusion • The p-value of .26173 is very high compared to our alpha level of .05, which means about 26% of the difference in awareness of the blog between the underclassmen and upperclassmen is due to natural sampling variation. We fail to reject the null hypothesis, as there is not enough evidence to suggest the difference in awareness is attributed to another source.
Confidence Interval 95% Confidence Level • Formula: Phat±z*(SE) • Margin of Error (z*(SE)): 1.96(.047) = .092 Calculation: .67 ± .092 = (.578, .762) Conclusion: We are 95% confident that the true proportion of students who are aware of the blog lies between . 578 (57.8%) and .762 (76.2%).
Improvements • Non response bias: it was difficult to find every student we randomly selected, as not everyone shows up to homeroom. • To reduce this bias, we could have sought them out in other ways, such as an office announcement or finding them in a class throughout the day. • Larger Sample Size • To reduce natural sampling variation, it might have helped to collect a larger sample. This also would have helped make up for the amount of students we weren’t able to track down. • We should change the question to: Did you know that NHS has a blog?
Thank you for listening!