Standard Deviation
Calculate the mean and median for the data set: 6, 7, 12, 8, 7, 4, 8, 8, 7
mean: 7.44 median: 7
Why do we randomly select our samples?
Reduce Bias
A value much greater or much less than the others in a data set.
Outlier
A public library asked every 10th person who entered to name the type of book they were getting.
Unbiased
#1 On the study guide: How many 7th graders had an IQ score in the 81-90 range?
13
If you score 76, 85, 97, and 83 on your math tests, what would your median score be?
84
Identify the Population: Wicomico County Public Schools randomly selected 230 teachers to find out which technology resource it's teachers feel is the most effective.
All Wicomico County Teachers
Identify the outlier for the given data? 23, 34, 27, 7, 30, 26, 28, 31, 34
7
Airline boarding passes are marked with red stars at random to decide which passengers should have their carry-on luggage inspected.
Biased
#3 On the study guide: A survey explored the relationship between gender and band class. Which is a reasonable conclusion?
More than half of the bands members in the class are girls
The front row in a movie theatre has 23 seats. If you were asked to sit in the seat that occupied the median position, in which seat would you have to sit?
Identify the Sample: A restaurant wants to know if their customers buy dessert when they eat out. As people leave the restaurant one evening, 20 people are surveyed at random. Eight people say they usually order dessert when they eat out. The restaurant concluded that most customers do not order dessert.
20 customers
Variables such as hair color, eye color, religion, favorite movie, gender, etc. are ____
Catigorical
To determine the most popular children’s programs, a television station asks parents to call in and complete a phone survey.
Unbiased Sample
#6 On the study guide: True of false, 75% of the data values are greater than 18?
False, 75% of the values are greater than 16
If I tell you that you scored at the 55th percentile on your final exam, you would know:
You earned a 55% on the exam
Assign each car in a dealership a number and then use a random-number table to select the cars to be inspected.
Simple Random Sample
A five-point summary on a line graph showing minimum, maximum, median, lower quartile, and upper quartile.
Box-and-Whiskers
To determine the most common injury cared for in an emergency room, a reporter goes to the same hospital every afternoon for one month during the summer and observes people entering the emergency room. She concludes that second-degree sunburn is the most common injury.
Unbiased
#11 On the study guide: What is the range in gas mileage for cars?
2
#2. On the study guide: Which class has the higher median?
2nd Period
Disneyland often surveys its guests as they exit a restaurant during their visit. The surveyor stands at the restaurant exit, counts the number of people leaving, and surveys every 25th guest. This is a form of:
Systematic Random Sampling
What types of graphs are used for categorical variables?
Pie Graphs, Bar Graphs
At a middle school, the 7th graders will conduct a survey to decide where they want to go on a field trip. Which method will result in the least biased decision?
To randomly choose some 7th grade students to select a location.
#23 On the study guide: How many students scored more than 80%?
13