Biased & Unbiased Samples
Identify the valid sampling method ( simple, stratified, or systematic)
To determine whether students think a new school library is needed, a computer generates a list of 100 random students and they are surveyed.
Simple Random Sample
If Duke won 35 out of 37 games. How many games would they win if they played 75 games?
70 games
Class scores for a test are posted and they read: 75, 80, 82, 85, 87, 90, 91, 93, and 100.
Find the mean and IQR
Mean=87
IQR=11
Q3 (92) - Q1 (81)
Average number of minutes spent on homework each night.
Middle School: 5,10,15,18,20,28,33
High School: 10,12,13,15,17,20,28
Does high school or middle school have a greater mean?
Middle School
A grocery store owner gives a discount to customers who take an online survey. Is this survey biased or unbiased? Was it a valid or invalid sampling method?
Biased
Invalid
Identify the valid sampling method ( simple, stratified, or systematic)
To determine the freshness of a doughnut, a baker selects a doughnut every 30 minutes and checks it
Systematic Random Sample
Tennessee has won 31 out of 40 games. If they were to play 105 games, how many games would you predict they would win?
81 games
11 friends went mini golfing. Their scores were: 16, 12, 9, 17, 21, 14, 12, 18, 17, 11, 13.
Find the median.
14
Average money spent by a person at McDonald's vs. Wendy's:
McDonald's: $6, $9, $12, $13, $13, $25, $27
Wendy's: $5, $5, $10, $17, $17, $20, $34
On average, who's food is more expensive?
Wendy's ($15.43)
When given a data set, if I do not have Q3 how would I find it?
Identify the valid sampling method ( simple, stratified, or systematic)
To determine if a candidate for state senator is popular with voters, 25% of voters in 160 countries are surveyed
Stratified Random Sample
Willie Beaman ran for 1,965 yards in 15 games. How many yards would you predict he would run for if he played 25 games?
3,275 yards
Find the IQR of this data set.
37,22,15,52,78,45,94,63
IQR=41
Q3(70.5)-Q1(29.5)
Below is a list of average dogs and cats speeds in miles per hour.
Cat: 7,7,8,8,9,9,10,11,13,14
Dog: 2,4,4,6,9,9,11,11,11,16
On average what animal runs faster?
Cats (9.6 mph)
When given a set of data, how would we find Q1 if it was not given?
Find the median of the first half of the data.
Give an example of a convenience sample
Answers may vary
Caitlin Clark made 175 three pointers in 60 games. How many threes would you predict she would make in an 82 game season?
239 threes
If the data is skewed what center of measure should we use?
Median
When comparing sets of data, how do we find the Interquartile Range (IQR)
Q3-Q1
22,4,13,6,35,8,7,49,10,1
Find the Minimum, Maximum, Q1, Q3, and the Median
Minimum-1
Maximum-49
Median-9
Q1-6
Q3-22
As people are leaving a restaurant, people are randomly sampled every 15 minutes. they sampled a total of 36 people. 6 say they usually order dessert. What type of sampling method did they use? What percentage of people usually order dessert?
Systematic Random Sample
16.67%
Tom Brady threw for 723 yards in a two game span.
Patrick Mahomes threw for 1497 yards in a four game span.
Who would you predict to throw more yards in a 17 game season?
Patrick Mahomes (6,362 yards)
If the data is uniform of symmetric what center of measure should we use?
Mean
when given two sets of data in a box plot, what are the 5 key elements we need?
i.e.: five number summary
Minimum
Q1
Median
Q3
Maximum
If Aaron Judge hit 35 home runs in 100 games and Mike Trout hit 54 in 162 games, who would you predict to hit more home runs in 200 games and how many would they hit?
Aaron Judge (70)