Vocabulary
Sampling
Bias
Standard Deviation
Not On Quiz, But Maybe on Test
100
What is the mode?
The most frequent, the most repeated, the most common value in a set of data.
100
Every 10th login to the NBA 2k online game has the gamer engage with a survey. What kind of sampling technique is this?
Systematic
100
When the survey sample does NOT accurately represent the ____, then the occurrence of bias is more.
Population
100
What is the symbol used for the mean?
Lowercase mu,
mu
100
Who came up with the normal distribution?
Gauss in 1809
200
What is the median?
Once a set of data values is arranged in order from least to greatest, the median will be the most middle value.
200
AMC surveyed all the customers in theater 1 and 5 on their movie experience. What type of sampling did they do?
Cluster
200
Eve polled the first 22 runners to finish a marathon. Is this sample of the runners likely to be biased?
Yes, there is likely to be bias since these are the fastest runners in the population
200
What is the symbol used for standard deviation?
A lowercase sigma,
sigma
200
If my score is m and your score is n, what is the probability that a random score, p, is
m < p < n?
68%
300
What is the mean?
The average of the data. Gotten by adding up all the data values, and then dividing by how many data values there were.
300
NextApp surveys 1,000 people randomly selected from these age groups: 8 - 13, 14 - 19, 20 - 25, 26 - 31. What type of sampling is this?
Stratified
300
A polling company wants to know how people feel about a new public policy. They randomly select 500 people from a national phone directory and call them to ask for their opinions. Is there bias?
No, there is likely no bias because the 500 people are selected randomly with no focus on any particular type of person.
300
What is standard deviation?
A specially calculated value relevant to the data that shows how spread out a normal distribution is. Also it determines how flat or tall the normal distribution is.
Extra:
sigma = sqrt((sum (x_i - mu)^2)/N)
300
A set of normally distributed data has a mean of 82 and a standard deviation of 5. If the z score is -1 for a data point, what is the data point?
77
400
What is a normal distribution?
It is the most common type of distribution, and as a sample increases in size the sample is more likely to display the normal bell curve shape.
400
Everyone writes down on a slip of paper which type of phone he or she has and drops it in a bucket. Of the 125 slips of paper, 30 are randomly selected. What type of sampling is this?
Simple Random
400
You want to choose a group of 40 students out of a class of 378 in order to conduct a study. The most unbiased way to do this is to:
A Ask your friends in the class to participate and have them also ask other people to participate.
B Have teachers recommend students for the study.
C Assign each member of the class a number from 1 – 378 and use a random integer generator to select 40 members.
D Advertise the study and have students volunteer depending on whether or not they are interested.
C Assign each member of the class a number from 1 – 378 and use a random integer generator to select 40 members.
400
If the mean is 500 and the standard deviation is 67, then what is the value of
mu - 1sigma
433
400
A data set is normally distributed with a mean of 78 and a standard deviation of 6.5. An element in this set is 72. Which is closest to the z-score for 72?
A 0.92
B 0.99
C -0.92
D -0.99
-0.92
500
What is the Central Limit Theory say?
That the mean, median, and mode become centralized in a normal distribution.
500
What type of data gathering is described as an equal number of samples being taken from each level?
Stratified
500
You are gathering data to determine the probability that a random person considers himself or herself a sports fan. To collect data, you ask people as they enter a sporting goods store. Is there bias in this sample. Why or why not?
Bias because of location
500
If the mean is 67 and the standard deviation is 3. Then what is the value of
mu + 3sigma
76
500
On a standardized test with normal distribution. The mean is 75 and the standard deviation is 6. If 1,200 students took the test, approximately how many students would be expected to score between 69 and 81?
816, 68% of 1200