Studies
You answer a set of questions online. What kind of study is that?
survey
Mr. Kibby randomly selects 20 students to answer questions about school lunches. What kind of sampling method did he use?
Simple random sampling
If you want to be really certain that you've captured the true population mean, should you use a 90% confidence level or a 99% confidence level?
99%
What is the theoretical probability of getting heads when you flip a coin?
50%
Is the number of sandwiches sold at Subway a discrete or continuous variable?
Discrete
Does a z-score of .5 mean that something is common or rare?
Common
Ms. Cohen provides one class with a notecard but not the other class to test whether notecards help on tests. What kind of study is that?
Experiment
Mr. Kibby asks every 15th student what their favorite color is. What kind of sampling did he use?
systematic sampling
If we were doing a survey of whether students or not students like using mechanical pencils, would we use a mean or a proportion for our statistical analysis?
proportion
I roll a six sided die 123 times and roll a three 29 times, what is the experimental probability of rolling a 3?
23.6%
Is distance to school a discrete or continuous variable?
Continuous
Calculate the z-score when X = 54, mean = 32, and standard deviation = 6.2
z = 3.55
Researchers look at video tapes of kids interacting with playdoh. What kind of study?
observational
Mr. Kibby writes in the morning announcements that students who want to share their opinion about the color of the sky should come to his office during lunch. What kind of sampling method did he use?
volunteer sampling
Calculate the margin of error with a 95% confidence level if sample size = 233, standard deviation = 6, mean = 57.
0.77
What is the theoretical probability that I roll a 3 on a 6-sided die?
16.7%
True or False: You should only use a normal distribution to approximate data if the data is symmetric
True
What would the standard deviation be if z = 2.53, X = 111 and mean = 86.
9.88
Mr. Kibby surveys every student in the school about the snack preferences of the Emery High student body. What kind of study?
census
A large group of students walked into the office and Mr. Kibby brought them all into his office, then chose two from each grade to complete a survey. Which two survey methods did he use?
Convenience sampling and stratified sampling
Ms. Cohen wants to be 90% confident when she shares the proportion of students who bring a pencil every day. She asks 73 students and finds that 52 of them bring a pencil every day. She knows the standard deviation is approximately 7 students. What should she announce as her confidence interval?
[0.625, 0.799]
As the number of times you flip a coin increases, what would you expect the experimental probability of getting tails to approach?
50%
Draw a normal distribution with mean = 53 and standard deviation = 4. Include three standard deviations away from the mean.
41 45 49 53 57 61 65
Mx. Combs reads 25 books every year on average, with a standard deviation of 4. What is the probability that they read less than 17 books in a year?
2.28%
You are interested in assessing whether drinking more water makes you focus better in class. What kind of study would be most appropriate?
Experiment
The lunch ladies hand a survey to everyone who comes in for pizza lunch and asks them to write what they think about pizza lunches. They collect the surveys at the end of the lunch period. Identify 2 possible sources of bias and explain how to fix the flaws in the study.
Students who come to lunch to eat pizza may like pizza more than the general population. The lunch ladies should ask during a different lunch day.
It's a volunteer sampling, which means only kids who feels strongly will respond. Students should be required to take the survey before they get their lunch.
A sample of 650 college students is surveyed about the number of credit hours they are taking this semester. The sample mean is 14.75 credit hours and the sample standard deviation is 2.25 credit hours. Use a 95% confidence level to estimate the mean for the credit hours and write the complete interpretation of the interval.
We are 95% confident that the number of credit hours is between 14.58 and 14.92.
In Dungeons and Dragons, most rolls are done with a 20-sided die, otherwise known as a d20. My character needs to beat a 14 in order to survive falling off a roof. What is the theoretical probability of that happening when I roll a d20?
30%
What percentage of the data would we expect to see within 1 standard deviation of the mean?
68%
In general for your birthdays, there are 15 people there on average, with a standard deviation of 5. What is the probability of having more than 17 people show up at your birthday party?
34.6%