Random Sample
Assign people a number and use a number generator to pick out the sample.
Simple Random Sample
Freemont Run Club surveyed a random sample of 30 of their members about their running habits. Of the members surveyed, 9 said that they run more than 5 days a week. There are 80 Freemont Run Club members. Make a prediction based on the sample.
24 run more than 5 days a week.
The average of a data set?
Mean
1/2 = x/4
x = 2
The likelihood of an event happening.
probability
Survey is going to be given to to 100 random students by giving 25 students from each grade level (5th, 6th, 7th, and 8th) the suvey.
Stratified Random Sample
Country: 25
Rock: 38
other:17
The total popultion is 2006.
Based on the data, what is the most reasonable estimate for the number of Throne County citizens whose favorite genre of music is rock?
276, 627, 401, or 953
953 people
the difference between the lower and upper extremes.
range
4/20 = x/25
x = 5
It can NOT happen.
impossible
sampling method where the researcher creates multiple groupings of people from a population to randomly survey them.
Cluster Random Sample
Francis surveyed a random sample of 70 students at Franklin High School about their favorite season. Of the students surveyed, 18 chose fall as their favorite season. There are 1816 students at Franklin High School. Based on the data, what is the most reasonable estimate for the number of students at Franklin High School whose favorite season is fall
257, 467, 515, or 1349
467 students
middle of my data set or Q2
Median
36/x = 45/10
x = 8
Equal chance to happen
50/50
if you were conducting surveys at a mall, you might survey every 100th person that walks in.
Systematic Random Sample
A group of randomly selected members of Mothers' Club were asked how many kids they have. There are 120 members in Mothers' Club.
1 kid = 9
2 kids= 6
3+ kids= 5
Based on the data, what is the most reasonable estimate for the number of Mothers' Club members who have fewer than 2 kids?
54 members
The highest and lowest numbers
Upper and Lower extremes
6/15 = x/20
x = 8
the number of ways the event can occur (favorable outcomes) divided by the number of total outcomes.
Thoretical Probability
Give an example of a NON random sample.
Convenient or voluntary
Bounce Club surveyed a random sample of 55 of their members about their favorite type of music. Of the members surveyed, 22 said that jazz is their favorite type of music. There are 422 Bounce Club members.
Based on the data, what is the most reasonable estimate for the number of Bounce Club members whose favorite type of music is jazz music?
22, 141, 169, or 253
169 members
the difference between Q1 and Q3 is...
Interquatile Range
3/4/10 = x/5
x = 1 1/2 or 1.5
Probability based on experiments.
Experimental Proability